The Dictionary Form -다 (좋다, 예쁘다, 크다)

Open any Korean dictionary and look up an adjective. You will find it listed as 좋다, 예쁘다, 크다, 조용하다, 맛있다 — always ending in -다. Look up an action verb and you find the same shape: 먹다 (to eat), 가다 (to go), 마시다 (to drink). The dictionary makes no visual distinction between "adjectives" and "verbs," and that is your first and best clue that in Korean the two classes conjugate alike. This page is about that -다 ending: what it is, how to strip it off, and — crucially — why you almost never actually say it.

-다 is a citation ending, not a spoken sentence

The -다 you see in the dictionary is the citation form (기본형, "base form"): the neutral label a word wears when it is being mentioned rather than used. It is the Korean equivalent of the English infinitive citation "to eat," "to be good" — the shape you look a word up under, not the shape you deploy in a live sentence.

To actually use an adjective, you strip off -다 and swap in a real ending: the everyday polite -아/어요, the formal -습니다, the attributive -(으)ㄴ, and so on. English speakers should think of -다 the way they think of "to be": you would never answer "How's the weather?" with "to be nice" — you would say "it's nice." Korean is the same. The dictionary lists 좋다, but to a person you say 좋아요 or 좋습니다.

Finding the stem: strip -다

Everything you build starts from the stem (어간), which is simply the citation form minus -다. Endings attach to the stem, never to the whole -다 word.

The stem is the fixed part; the ending is the changing part. That divide is the entire engine of Korean conjugation, and it works identically for adjectives and action verbs — 먹다 has the stem 먹-, 가다 has the stem 가-, exactly the way 좋다 has 좋- and 크다 has 크-. See the verb dictionary form for the action-verb side of the same picture.

Why the stem's final sound matters

Notice the last column in the table. A stem ending in a batchim (a final consonant, like 좋- or 작-) and a stem ending in a vowel (like 예쁘- or 크-) behave differently the moment you add an ending that begins with a vowel. A batchim-final stem just takes the ending onto it (좋- + -아요 → 좋아요). A vowel-final stem often contracts or drops a vowel (크- + -어요 → 커요, not ×크어요). You do not need to master those changes here — the point is that finding the stem and noticing how it ends is the prerequisite for everything downstream. The two vowel-final shapes that change most are handled on the 으-drop page (예쁘-, 크-) and the 하다 page (조용하-).

When -다 IS spoken: the plain style (a labeled exception)

If -다 is just a lookup form, why do Korean speakers say things like 배고프다 out loud? Because -다 is also the ending of a genuine speech style — the plain style (한다체 / 해라체) — used for two things: written narration (diaries, novels, news, factual prose) and spoken exclamations to oneself.

Written/narrative plain style. In a diary or a novel, adjectives end in bare -다:

Exclamatory plain style. When you blurt out a reaction — to yourself, or in casual company — the plain -다 comes out with feeling. This is real, everyday spoken Korean:

The catch — and it is the exact trap this page exists to prevent — is that this plain -다 is not a neutral, all-purpose statement you can direct at a listener politely. Said flatly to your boss, 날씨가 좋다 sounds like you are muttering to yourself or writing a report, not addressing them. The full mechanics of the plain style live on the plain present -ㄴ다/는다 page and the speech-levels overview; here, just hold onto the rule below.

Talking about words themselves

Because -다 is the "naming" form, it is also what you use when you quote a word as a word — in a lesson, a dictionary, or a grammar note. This is natural, everyday metalanguage:

Here 조용하다 stays in its citation form because you are referring to the word, not using it to describe anything. The moment you actually describe a quiet room, it becomes 조용해요 or 조용한 (attributive).

Common Mistakes

1. Speaking the dictionary form to someone as a polite statement. -다 is not polite; it is neutral/plain.

2. Adding an ending onto the whole -다 form. Strip -다 first.

3. Forgetting to strip -다 before conjugating a vowel-stem word. The stem of 예쁘다 is 예쁘-, not 예쁘다-.

4. Spelling the word the way it sounds and losing the stem's batchim. 좋아요 is pronounced [조아요], but the stem is 좋-, so the ㅎ stays in the spelling.

Key Takeaways

• Every adjective (and every action verb) is listed in the dictionary ending in -다 — the citation form, not a spoken sentence.
• To use a word, strip -다 to get the stem (좋다 → 좋-, 예쁘다 → 예쁘-, 크다 → 크-), then add a real ending.
• A stem ending in a batchim vs a vowel conjugates differently downstream — noticing the stem's final sound is step one.
• Bare -다 is spoken in the plain style: written narration and self-directed exclamations (아, 좋다!). It is not a polite statement to a listener.
• Because both classes use -다, the ending tells you nothing about whether a word is a verb or an adjective — that is learned per word, and it matters (see the verb/adjective divide).