Adverb -히 -이 in Korean: Meaning, Rules and Examples

What you'll learn

• Recognize adverbs that end in -히 or -이 and say what they mean.
• Build common ones from 하다 adjectives: 조용하다 to 조용히.
• Choose between 히 and 이 using the spelling logic and a dictionary.
• Avoid invented forms such as 예쁘히 and the misspelling 깨끗히.

Prerequisites: the idea of an adverb from Korean adverbs and the lesson on adverb -게 in korean. Time: about 15 minutes.

Key facts

• An adverb is a word that describes a verb, an adjective or another adverb, and in Korean it stands before the word it describes.
• -히 and -이 words are learned one by one, because the list is fixed.
• Many of them come from 하다 adjectives: 조용하다 gives 조용히.
• The ending 이 is used after ㅅ-stems, some ㅂ-irregular stems and repeated nouns.
• Greetings use them too: 안녕히 가세요 and 안녕히 계세요.

Listen to the two model sentences for this lesson.

The next section defines the endings and shows two annotated examples.

What Does the Adverb -히 -이 in Korean Mean?

The adverb endings -히 and -이 turn a word into an adverb that says how an action is done. The ending itself carries no meaning of its own. The meaning belongs to each word: 천천히 is "slowly", 조용히 is "quietly" and 깨끗이 is "cleanly". Because there is no rule to apply to a new adjective, a learner meets these adverbs as vocabulary, not as a grammar pattern.

The ending -게 works the other way. It can be added to almost any adjective stem, which makes it productive. The ending -히/-이 is lexical, which means that it belongs to the word and has to be remembered with it.

A First Example

In both sentences the adverb stands directly before the verb. The next section shows where these words come from.

How Are -히 and -이 Adverbs Formed?

Most -히 and -이 adverbs come from a few predictable sources, and the table groups them. The groups help memory, but they do not replace a dictionary.

Four points keep the table in perspective.

The -히 group is large. 조용히, 천천히, 열심히, 가만히, 분명히, 충분히, 확실히 and 안녕히 are among the most common adverbs in the language. Learn them as whole words and add a new one when you meet it.

The -이 group is smaller. It includes 깨끗이, 가까이, 많이, 같이, 높이, 깊이 and the repeated nouns.

Not every adjective has a form. 예쁘다, 크다 and 맛있다 have no -히 or -이 adverb. They use -게: 예쁘게, 크게, 맛있게. Words like 예쁘히 and 크이 do not exist.

Spoken forms hide the difference. 많이 sounds like [마니], because the ㅎ in ㄶ is silent before a vowel. 같이 sounds like [가치], because ㅌ before 이 becomes [ㅊ]. 깨끗이 sounds like [깨끄시], because the final ㅅ moves onto the next syllable.

The next section explains the spelling logic.

How Do You Choose between -히 and -이?

The choice follows a spelling rule that is based on sound, and a rule of thumb helps. Article 51 of the Korean Spelling Rules (한글 맞춤법), which is among the language rules (어문 규정) kept by the National Institute of Korean Language (국립국어원), says: write -이 when the ending clearly sounds like 이 only, and write -히 when it sounds like 히 only or when both can be heard.

In practice the sound is hard to hear, so use three working rules.

1. ㅅ before the ending. If the root ends in ㅅ, write 이: 깨끗이, 따뜻이, 반듯이.
2. Repeated nouns. Write 이: 집집이, 곳곳이, 번번이.
3. Other 하다 adjectives. Write 히: 조용히, 간단히, 정확히.

Rule 1 has a well-known trap. 깨끗하다 is a 하다 adjective, so learners expect 깨끗히. The correct spelling is 깨끗이, because the root ends in ㅅ. When a word falls outside the three rules, such as 열심히, 특히 or 많이, look it up in the Standard Korean Dictionary (표준국어대사전).

The next section builds one sentence step by step.

Worked Example: Building 천천히 걸어요

To say "I walk slowly", start from the meaning and build the sentence in five steps.

1. Name the manner. The idea is "slowly, without hurry".
2. Find the adverb. The word is 천천히. It is a fixed form, so you look it up and do not build it.
3. Choose the verb. "Walk" is 걷다, which becomes 걸어요 in the polite form (a ㄷ-irregular stem).
4. Place the adverb before the verb. 천천히 걸어요.
5. Add a topic if you like. 저는 천천히 걸어요 means "I walk slowly" with the subject named.

You'll know it worked when 천천히 stands next to the verb with no particle between them. To make a request, add 주세요: 천천히 말해 주세요 means "Please speak slowly". The position of other adverbs in a sentence is covered in Korean adverb position in a sentence.

The next section compares these adverbs with the ending -게.

How Is -히/-이 Different from -게?

The two kinds differ in how they are made. -게 is a rule you apply, and -히/-이 is a word you learn. Both describe how an action is done, and both stand before the verb.

Some words have both forms, with nearly the same meaning: 조용히 and 조용하게, 깨끗이 and 깨끗하게, 따뜻이 and 따뜻하게. The -히/-이 form is shorter and slightly more fixed, and the -게 form is easier to extend. Compare 깨끗이 닦아요 with 깨끗하게 닦아요, which is [깨끄타게 다까요]. Both mean "I wipe it clean".

For adjectives without a -히 form, -게 is the only choice. The complete -게 lesson is adverb -게 in korean.

What this lesson does not cover. It does not cover the mimetic adverbs such as 반짝반짝, which have their own lesson in korean mimetic words adverbs 반짝반짝. It also does not list every -히 word.

An honest limit. Whether a word has a -히 or -이 form is a fact about the word. A dictionary is the final check, and different textbooks teach slightly different sample lists.

The next section covers details that cause trouble in practice.

Edge Cases: Greetings, Look-Alikes and 빨리

Four details help learners sound natural.

안녕히 is an adverb in a greeting. 안녕히 가세요 means "Goodbye" to the person who is leaving, and 안녕히 계세요 means "Goodbye" to the person who stays. 안녕히 주무세요 means "Sleep well". The greeting word is the adverb 안녕히, and the verb 가세요, 계세요 or 주무세요 follows.

Some look-alikes are different words. 반듯이 means "straight, upright" and 반드시 means "without fail, certainly". They sound the same ([반드시]), so spelling is the only difference. 반드시 숙제를 하세요 means "Be sure to do your homework."

빨리 and 멀리 are separate words. 빨리 ("quickly") is related to 빠르다, and 멀리 ("far away") is related to 멀다. Learn them as vocabulary, as you do 천천히. You would not build them from a rule.

Some of these words have more than one use. 많이 means "a lot" (많이 먹어요), and 같이 means "together" (같이 가요), but 같이 also appears as a particle meaning "like", which belongs to a different lesson.

The next section lists the errors that appear most often.

What Mistakes Do Learners Make with -히 and -이?

Learners make seven predictable mistakes. Each one has a reason and a fix.

Learners often assume any adjective can take -히. Actually only listed words can. Wrong: 예쁘히 웃어요. Right: 예쁘게 웃어요. Fix: use -게 when you are not sure.

Learners often assume any adjective can take -이. Actually the same limit applies. Wrong: 크이 말해요. Right: 크게 말해요. Fix: look in the dictionary before you use a new -이 form.

Learners often spell 깨끗이 with 히. Actually the root ends in ㅅ. Wrong: 깨끗히. Right: 깨끗이. Fix: remember the ㅅ rule.

Learners often spell 열심히 with 이. Actually it is a listed -히 word. Wrong: 열심이 해요. Right: 열심히 해요. Fix: treat 열심히 as one memorized word.

Learners often spell the repeated nouns with 히. Actually they take 이. Wrong: 집집히. Right: 집집이. Fix: repeated nouns always end in 이.

Learners often build 빠르히 or 멀이. Actually these words are 빨리 and 멀리. Right: 빨리 와요, 멀리 가요. Fix: learn the adverb as its own word.

Learners often put the adverb after the verb. Actually Korean puts it before. Wrong: 걸어요 천천히. Right: 천천히 걸어요. Fix: finish the sentence with the verb.

Practice turns these rules into habits, as the next section shows.

Practice and Answers

Complete the four tasks, then compare your answers with the key.

Task 1: choose the spelling. Write the correct adverb for each meaning.

1. "cleanly" (깨끗하다)
2. "quietly" (조용하다)
3. "house by house" (집)
4. "hard, diligently"

Task 2: fix the error. Each phrase has one mistake. Rewrite it correctly.

1. 깨끗히 닦아요
2. 예쁘히 웃어요
3. 걸어요 천천히

Task 3: translate. Write in Korean: "Please be quiet." and "I wipe it clean."

Task 4: write your own. Write one sentence about how you study or walk, using 천천히 or 열심히.

Answer key

1. (1) 깨끗이 (2) 조용히 (3) 집집이 (4) 열심히.
2. (1) 깨끗이 닦아요 (2) 예쁘게 웃어요 (3) 천천히 걸어요.
3. 조용히 해 주세요. 깨끗이 닦아요.
4. Sample answers: 저는 열심히 공부해요 ("I study hard."), 저는 천천히 걸어요 ("I walk slowly.").

If task 1 was correct, you have the spelling logic. If task 2 was hard, return to the section on choosing between -히 and -이. The next section points you to the lessons that follow.

Next Lessons after the Adverb -히 -이

After the adverb -히 -이, read adverb -게 in korean if you have not yet, and then Korean adverbs of degree 아주 너무 정말 for words that say how much. The wider area is described on the parent page, Korean adverbs.

This lesson covers the fixed adverbs ending in -히 or -이 and the spelling logic behind them. It does not cover mimetic adverbs or every word in the list. About this page. Last updated 2026-10-09. The Korean text and spoken forms on this page were generated with AI assistance. Romanization follows the Revised Romanization of Korean and is shown only as a learning aid.

Frequently Asked Questions

What does -히/-이 mean? -히 and -이 are endings that turn a word into an adverb, a word that describes a verb or an adjective. 천천히 means "slowly", 조용히 means "quietly" and 깨끗이 means "cleanly". They appear in a closed list of words that must be learned one by one. 천천히 걸어요 means "I walk slowly".

How do I form -히/-이? Most 하다 adjectives swap 하다 for 히: 조용하다 gives 조용히, and 간단하다 gives 간단히. Stems with a root that ends in ㅅ take 이: 깨끗하다 gives 깨끗이. Some ㅂ-irregular adjectives and repeated nouns also take 이: 가깝다 gives 가까이, and 집 gives 집집이. Check each word in a dictionary.

What is the most common mistake with -히/-이? The most common mistake is inventing a form from any adjective, as in 예쁘히 or 크이. These words do not exist, because -히/-이 is a fixed list and not a rule. The correct forms are 예쁘게 and 크게. A second mistake is the spelling 깨끗히, which should be 깨끗이.

How is -히/-이 different from -게? -게 can be added to almost any adjective stem, so it is productive: 예쁘게, 크게, 맛있게. -히/-이 belongs to a fixed list: 천천히, 조용히, 깨끗이. A few words have both forms with a similar meaning, such as 조용히 and 조용하게, and the -히 form is the shorter one.

Do I use -히/-이 in speech, writing or both? Both. 천천히, 조용히 and 열심히 are everyday spoken words, and 특히 and 충분히 are common in writing. The greeting 안녕히 가세요 is spoken to someone who is leaving. The spelling rule matters most in writing, because 히 and 이 can sound alike at the end of a word.

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