LESSON NOTES · レッスンノート

Lesson notes · Sep 29, 2026

Honki (本気ほんき) meaning: "serious" in Japanese and the four other words for it

本気ほんき (honki) means "in earnest" or "for real": your feelings and intentions are genuine, not a joke and not half-hearted — and it is only one of five Japanese words that English squeezes into "serious".

Search for "serious in Japanese" and you get a single answer, usually 真面目まじめ or 本気ほんき, with no explanation of why there are two. There are really five, and each one picks out a different thing that English calls serious: a feeling, a focus, a personality, a situation, a weight. This article starts with 本気ほんき and then sorts out the rest, so you stop reaching for the wrong one.

The basics

What does 本気ほんき (honki) mean?

It means that the feeling or intention behind what you say or do is real. The kanji are 本ほん (true, real) and 気き (spirit, mind, feeling), so the word is literally "a real mind". You use it about how committed someone is, not about how solemn or grave something is.

前まえはあまり本気ほんきじゃなかったけど、今いまは本気ほんきです。 — I wasn't very serious before, but now I am. (polite; the classic way to talk about how committed you are to studying) 本気ほんきで日本語にほんごを勉強べんきょうしています。 — I'm studying Japanese for real. (polite; 本気ほんきで works like an adverb)

If you can replace "serious" with "in earnest", "for real" or "not kidding", 本気ほんき is probably your word.

How do you use 本気ほんき in a sentence?

Four patterns cover almost everything: 本気ほんきだ, 本気ほんきで, 本気ほんきを出だす and 本気ほんきにする. Learn them as a set, because each one has a different job.

Pattern Meaning Example
本気ほんきだ / 本気ほんきです I mean it; I'm serious 私わたしは本気ほんきです
本気ほんきで + verb do something for real 本気ほんきで走はしる
本気ほんきを出だす go all out; stop holding back 今日きょうは本気ほんきを出だす
本気ほんきにする take something seriously; believe a joke 冗談じょうだんを本気ほんきにする
本気ほんき? Are you serious? えっ、本気ほんき?

私わたしは本気ほんきです。 — I mean it. (polite, stating your commitment) 本気ほんきで走はしったら、間に合まにあいました。 — When I ran for real, I made it in time. (neutral) 冗談じょうだんを本気ほんきにしないでください。 — Please don't take the joke seriously. (polite request) えっ、本気ほんき? — Wait, are you serious? (casual; rising tone, and the question mark does the work of a question)

Notice that 本気ほんきにする is the odd one. It is not "be serious" but "treat someone else's words as serious", which usually means you believed something that was only a joke.

Which other words mean "serious", and how are they different?

Each word points at a different thing. English "serious" is one word for at least five Japanese ideas, and this table is the single most useful thing to keep from the article.

Word Reading What is serious Typical partner
本気ほんき ほんき The feeling is real 本気ほんきで好すき, 本気ほんきを出だす
真剣しんけん しんけん You are focused and giving it full attention 真剣しんけんな顔かお, 真剣勝負しんけんしょうぶ
真面目まじめ まじめ A person's character is earnest and reliable 真面目まじめな人ひと
深刻しんこく しんこく A situation is grave 深刻しんこくな問題もんだい
重おもい おもい Something has real weight (illness, crime) 重おもい病気びょうき

彼かれは真面目まじめな人ひとです。 — He is a serious, dependable person. (polite; describes character) これは深刻しんこくな問題もんだいです。 — This is a serious problem. (polite; describes a situation) 先生せんせいは真剣しんけんな顔かおで話はなしました。 — The teacher spoke with a serious face. (neutral; focused expression)

Here is the short version. If you are asking "does he mean it?", use 本気ほんき. If you are asking "is he concentrating hard?", use 真剣しんけん. If you are describing what kind of person he is, use 真面目まじめ. If the topic is a bad situation, use 深刻しんこく. If it is an illness or a crime with real weight, use 重おもい.

Beyond the basics

What is the difference between 本気ほんき and 真剣しんけん?

本気ほんき is about whether you mean it; 真剣しんけん is about how hard you are concentrating while you do it. The two overlap, which is why learners mix them up, but they can come apart.

You can be 本気ほんき about something without looking 真剣しんけん at all: someone can be laughing and still be completely 本気ほんき about a plan. And you can look 真剣しんけん without saying anything about your plans: a person bent over careful, focused work is 真剣しんけん — the word describes the attitude you can see, while 本気ほんき is about what you intend. The word 真剣勝負しんけんしょうぶ (a match fought with everything on the line) shows the 真剣しんけん flavour: total attention, no room for play.

真剣しんけんに聞きいてください。 — Please listen carefully and seriously. (polite; asking for full attention) この仕事しごとには本気ほんきで取り組とりくんでいます。 — I'm approaching this work in earnest. (polite; the commitment is genuine)

As a rough test, 真剣しんけん pairs naturally with 顔かお (face), 目め (eyes) and 話はなし (talk), things you can see. 本気ほんき pairs with 好すき (like), 出だす (bring out) and 思おもう (think), things that happen inside. (真剣しんけんに好すき is also possible; it means "seriously, committedly in love".)

How does 本気ほんき sound in anime?

Anime uses 本気ほんき as a dramatic switch: the moment a character stops holding back. If you have watched a fight scene, you have already heard it.

今いまから本気ほんきを出だす。 — From now on I go all out. (casual, masculine; the fight-scene classic) 本気ほんきでいくぞ! — I'm coming at you for real! (casual, shouted) 本気ほんきで言いってるの? — Are you seriously saying that? (casual; disbelief) 俺おれは本気ほんきだ。 — I mean it. (casual, masculine; the だ ending sounds firm and a little dramatic)

本気ほんきを出だす is the pattern to remember. The character has been fighting at a lower level, and 本気ほんきを出だす announces that the real level is coming. It is the same energy as "now I'm not holding back" in English. The opposite is 手加減てかげんする (to go easy on someone), which you will hear from the opponent who is annoyed at being underestimated.

What is マジ, and can you use it with everyone?

マジ is casual slang for "seriously" or "for real", and it comes from 真面目まじめ (まじめ), but it now behaves like a general intensifier. It has three main uses:

  • マジで? — "Really?" / "Seriously?"
  • マジで + adjective or verb — "really", as in マジでおいしい
  • マジだ — "It's for real"

マジで? 知しらなかった。 — Seriously? I didn't know. (casual, with friends) このラーメン、マジでおいしい。 — This ramen is really good. (casual, intensifier) それ、マジだよ。 — That's for real, you know. (casual; assurance)

Keep マジ for friends, family and people your age. It sounds sloppy or disrespectful to a boss, a teacher or a customer. With them, use 本当ほんとうですか (Is that true?) or 本気ほんきですか (Are you serious about it?), both polite. In manga you may also see the word 本気ほんき written with the reading マジ above it. That is a stylistic choice by the author: the characters are written as 本気ほんき, but the sound is the slangy マジ, which gives the line a tougher, more youthful edge.

Can 本気ほんき be an adjective?

Yes, but mostly with 本気ほんきの. You will see 本気ほんきの恋こい (love that is for real) or 本気ほんきのプレー (all-out play). Before a noun, use 本気ほんきの. After a verb, the adverb 本気ほんきで is more common.

これは本気ほんきの恋こいです。 — This is real love, not a fling. (neutral; 本気ほんきの modifies a noun) みんな本気ほんきで応援おうえんしています。 — Everyone is cheering for real. (neutral)

For more on how words get their nuance from the situation, see てっきり, where the same kind of pattern (one English idea, several Japanese shades) shows up again.

What about the competitive kind of serious?

That is a different word again: 負まけず嫌きらい. A person who hates to lose plays with real 本気ほんき, but the word for the trait is 負まけず嫌きらい, not 本気ほんき. We sort out that pair, and how it differs from simply trying hard, in 負まけず嫌きらい. And if you want the kind of serious that takes courage, a related feeling, see 勇気ゆうき.

Common mistakes

  • Using 深刻しんこく for a person's character. 深刻しんこくな人ひと does not mean "a serious person". It sounds like someone who is heavy or gloomy about things. For a serious, earnest personality, say 真面目まじめな人ひと.
  • Using 真面目まじめ for a situation. 真面目まじめな問題もんだい is not the usual way to say "a serious problem". 真面目まじめ mostly describes people and attitudes (真面目まじめな話はなし is "a serious talk"); a serious problem is 深刻しんこくな問題もんだい.
  • Mixing up 本気ほんき and 真剣しんけん. 本気ほんき answers "do you mean it?" and 真剣しんけん answers "are you concentrating?". You can say 本気ほんきで好すき (I really like it), but not 真剣しんけんで好すき: 真剣しんけん takes に or な (真剣しんけんに考かんがえる, 真剣しんけんな顔かお). 真剣しんけんに好すき is possible, but it sounds like a serious, committed love, as in 真剣しんけんに付き合つきあう.
  • Using マジ with your boss or teacher. It is friendly slang. Use 本当ほんとうに or 本気ほんきで with anyone you should be polite to.
  • Translating 本気ほんきにする as "be serious". It means to take someone else's words at face value, usually a joke.

The politeness ladder

Register Form Example
Polite / formal 本気ほんきです, 本当ほんとうですか 私わたしは本気ほんきです
Neutral 本気ほんきで + verb 本気ほんきで頑張がんばる
Casual 本気ほんき? / 本気ほんきだよ えっ、本気ほんき?
Slang マジ? / マジで? マジで?

Practice

Build each answer before opening it. Questions 3 and 4 are a pair, and so are 5 and 6: same English word, different Japanese.

1. Say "I'm serious" (I mean it), politely.

Show answer

私わたしは本気ほんきです — the feeling is real, so 本気ほんき, and です makes it polite.

2. In an anime, a character has been holding back and announces he will now go all out. Which pattern is that?

Show answer

本気ほんきを出だす — 出だす (to bring out) plus 本気ほんき means to stop holding back. 本気ほんきを出だす is the standard fight-scene line.

3. How do you say "He is a serious person" (earnest, reliable character)?

Show answer

彼かれは真面目まじめな人ひとです — 真面目まじめ describes a personality.

4. How do you say "This is a serious problem"?

Show answer

これは深刻しんこくな問題もんだいです — 深刻しんこく describes a grave situation. 真面目まじめな問題もんだい is not the usual wording, because 真面目まじめ mostly describes people and attitudes.

5. A friend makes a joke, but you take it as true. Which word: 本気ほんきにする or 本気ほんきだ?

Show answer

本気ほんきにする — you took his words seriously. 本気ほんきだ would mean that you yourself mean something.

6. You want to say "I really do like this anime" for real. Which fits: 本気ほんきで好すき or 真剣しんけんで好すき?

Show answer

本気ほんきで好すき — the feeling is genuine, so 本気ほんき. 真剣しんけんで好すき is not grammatical; 真剣しんけん takes に (真剣しんけんに好すき), and that sounds like a committed, serious love.

7. Which word fits: 先生せんせいは(真剣しんけん・深刻しんこく)な顔かおで話はなした, "The teacher spoke with a serious, focused face"?

Show answer

真剣しんけん — a focused, attentive expression. 深刻しんこくな顔かお would mean a grave, worried face, which is a different picture.

8. Your teacher says something surprising. Ask "Is that true?" politely instead of マジで?.

Show answer

本当ほんとうですか (or 本気ほんきですか, if you mean "do you really mean it?") — マジで? is slang and too casual for a teacher.

9. Which is the standard word for the severity of an illness: 重おもい病気びょうき or 深刻しんこくな病気びょうき?

Show answer

重おもい病気びょうき — 重おもい (heavy) is the standard word for how severe an illness or crime is. 深刻しんこくな病気びょうき is also said, but it stresses how worrying the situation is.

During a trial lesson, act out a confession and a fight scene, and choose between 本気ほんき, 真剣しんけん and 真面目まじめ depending on whether you mean the feeling, the focus or the person.

FAQ

Is 本気ほんき the same as マジ? They overlap, but マジ is casual slang and 本気ほんき is not. マジで? and 本気ほんき? can both mean "Are you serious?" among friends, but 本気ほんきですか or 本当ほんとうですか works politely.

What is "serious" in Japanese in hiragana? The common ones are ほんき (本気ほんき), しんけん (真剣しんけん), まじめ (真面目まじめ) and しんこく (深刻しんこく). Which one you need depends on what is serious: a feeling, a focus, a person or a situation.

How do you say "seriously" in Japanese? For "for real", use 本気ほんきで. For "seriously?" among friends, use マジで?. For "really" as a polite intensifier, use 本当ほんとうに.

What does 本気ほんきだ mean? It means "I'm serious" or "I mean it". The だ makes it casual and firm, so it is common in anime dialogue.

Can 本気ほんき be used for things, not only people? Mostly it is about people and their intent, though you can say 本気ほんきの勝負しょうぶ (a real contest) or 本気ほんきの恋こい (real love). For a serious situation, use 深刻しんこく.

Vocabulary from this article

Tap the block to select all of it, then copy. In Anki: File → Import, note type Basic, separator Tab — the first column becomes the front, the second the back.

本気	ほんき — in earnest, for real
真剣	しんけん — serious, earnest, focused
真面目	まじめ — earnest, diligent (personality)
深刻	しんこく — serious, grave (situation)
重い	おもい — heavy, serious (illness)
本気を出す	ほんきをだす — to go all out
本気にする	ほんきにする — to take seriously, to believe a joke
マジ	まじ — seriously, for real (slang)
冗談	じょうだん — joke
問題	もんだい — problem
病気	びょうき — illness
勝負	しょうぶ — match, contest
恋	こい — love, romance
顔	かお — face
手加減する	てかげんする — to go easy on

I'm Yuuki, a Japanese teacher based in Tokyo. I've taught on italki as a Top 1% teacher and watched over 1,500 anime, so most of the example sentences on this blog come from lines I've actually heard in fights and confessions. The 本気ほんき versus 真剣しんけん mix-up is one of the ones that comes up again and again in lessons. For practice with feedback, Book a trial lesson · $13, or work through Japanese practice exercises first.

Sources: the author's own lessons and standard reference grammars.

More drills like the ones above, plus a timed JLPT-style mock test: Practice

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