The Minor Causatives -구- and -추- | Korean Grammar

The seven fused causative suffixes are not equal in weight. 이/히/리/기 do the heavy lifting; 우 handles the vowel stems; and then there are -구- and -추-, the two rarest, each surviving in only a small closed set of verbs. This page teaches them together, because the honest lesson for both is the same: do not try to generate them. No productive rule will tell you that 늦다 becomes 늦추다 — you simply learn each verb as its own vocabulary item. What makes the pair worth a dedicated page is that a couple of their members (especially 맞추다) are extremely high-frequency and sit at the center of two famous spelling-and-meaning traps that even native speakers stumble over.

-구-: a handful of fossils

-구- appears in only a few lexicalized verbs. You will meet these as vocabulary, not as a pattern:

Base verb	Causative	Romanization	Meaning
달다 (glow hot)	달구다	dalguda	heat [metal, a room] up
일다 (rise, form)	일구다	ilguda	till, cultivate, build up
솟다 (soar, gush)	솟구다	sotguda	make surge up (literary)
돋다 (rise, sprout)	돋구다	dotguda	raise the strength of eyeglasses (only)

달구다 is the liveliest of the set. From 달다 ("become red-hot"), it means to heat something up — literally a blacksmith's iron, or figuratively a room, a crowd, or an atmosphere (분위기를 달구다 "get the mood going").

대장장이가 쇠를 벌겋게 달궜어요.

daejangjang-iga soereul beolgeoke dalgwosseoyo

The blacksmith heated the iron until it glowed red.

일구다 ("till, cultivate; build up from nothing") carries a slightly literary, effortful ring — you 일구다 farmland, or a fortune, or a life built by hard work. Its base 일다 is itself old and rare.

할아버지는 평생 이 땅을 일구셨어요.

harabeojineun pyeongsaeng i ttang-eul ilgusyeosseoyo

Grandfather cultivated this land his whole life.

솟구다 is genuinely rare (literary); in ordinary Korean the intransitive 솟구치다 ("surge/well up") does almost all the work — 눈물이 솟구치다 ("tears well up"). Recognize 솟구다 in writing, but do not reach for it in speech.

돋구다 vs 돋우다 — a trap worth memorizing

Here is the first classic pitfall. Standard Korean restricts 돋구다 (the -구- form) to exactly one meaning: raising the prescription strength of eyeglasses (안경 도수를 돋구다). Every other "raise / whet / provoke" sense uses 돋우다, which is a -우- verb, not a -구- verb:

입맛을 돋우다 — whet the appetite
화를 돋우다 — provoke, get someone's anger up
흥을 돋우다 — heighten the fun/mood

안경 도수를 좀 돋궈야겠어요.

angyeong dosureul jom dotgwoyagesseoyo

I should raise the strength of my glasses. (돋구다 — the eyeglass sense only)

매운 음식이 입맛을 돋워요.

maeun eumsigi immaseul dodwoyo

Spicy food whets the appetite. (돋우다 — everything else)

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If you are raising anything other than the power of your glasses — an appetite, a mood, someone's temper — the verb is 돋우다 (from -우-), not 돋구다. Most Koreans get this "wrong" in casual speech, which is exactly why it appears on proficiency tests.

-추-: causatives of degree

-추- is a little more systematic in feel: it tends to build "adjust to a degree" causatives out of stems about height, timing, and fit. Still, the membership is a closed list of four:

Base verb	Causative	Romanization	Meaning
낮다 (be low)	낮추다	natchuda	lower
늦다 (be late)	늦추다	neutchuda	delay, slow, loosen
맞다 (fit, be right)	맞추다	matchuda	adjust, set, match, align, tailor
갖다 (have)	갖추다	gatchuda	equip, furnish, prepare

목소리를 조금만 낮춰 주세요.

moksorireul jogeumman natchwo juseyo

Please lower your voice a little.

늦추다 covers a whole range of "ease off" meanings — pushing a time back, slowing a pace, loosening tension or a knot: 시간을 늦추다, 속도를 늦추다, 긴장을 늦추다.

회의를 삼십 분 늦췄어요.

hoeuireul samsip bun neutchwosseoyo

We pushed the meeting back thirty minutes.

갖추다 ("equip, be furnished with") leans (formal) and written — you 갖추다 the conditions (조건을 갖추다), the required documents (서류를 갖추다), or good manners (예의를 갖추다). It is not the everyday word for "have"; that is 있다 or 가지고 있다.

이 식당은 모든 조건을 갖췄어요.

i sikdang-eun modeun jogeoneul gatchwosseoyo

This restaurant meets all the requirements.

맞추다 — high-frequency and polysemous

맞추다 is the one verb on this page you truly cannot avoid, and it is wildly polysemous. Its unifying idea is bringing two or more things into correspondence — aligning, coordinating, setting one thing to another:

알람을 맞추다 — set an alarm
시간을 맞추다 — set / synchronize a time
색깔을 맞추다 — match colors
간을 맞추다 — adjust the seasoning
옷을 맞추다 — have clothes custom-made / tailored
줄을 맞추다 — line things up in a row

알람을 여섯 시에 맞췄어요.

allameul yeoseot sie matchwosseoyo

I set the alarm for six.

맞추다 vs 맞히다 — the trap at the heart of this page

Both come from 맞다, but they have split into two different causatives with two different meanings, and confusing them is one of the most common errors in written Korean:

맞추다 (matchuda) = bring things into correspondence — align, coordinate, compare against a standard.
맞히다 (machida) = cause to be correct or to connect — hit a target, guess/answer correctly, expose someone to something.

The textbook battleground is answers on a test:

정답을 맞힌 사람이 없었어요.

jeongdabeul machin sarami eopseosseoyo

Nobody got the right answer. (맞히다 — get it right / guess correctly)

시험 끝나고 친구랑 답을 맞춰 봤어요.

siheom kkeunnago chingurang dabeul matchwo bwasseoyo

After the exam I checked my answers with a friend. (맞추다 — compare answers against each other)

To get the answer right is 맞히다; to compare your answers against a key or a friend's is 맞추다. Same for a dartboard: 과녁을 맞히다 ("hit the target"), never ×맞추다. And a shot at the doctor's is 주사를 맞히다 ("give an injection," causing someone to be hit by the needle).

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맞히다 = get it right / hit it (정답을 맞히다, 과녁을 맞히다). 맞추다 = line it up / coordinate it (시간을 맞추다, 옷을 맞추다). When you mean "answered correctly," it is always 맞히다 — 맞추다 there is the single most-flagged native error.

The honest summary: memorize, do not generate

Because -구- and -추- together cover only a handful of verbs, there is no payoff in trying to derive them. English has nothing like this — English builds all its causatives analytically ("make it lower," "have it adjusted"), so there is no habit to transfer and nothing to reason from. Store 달구다, 일구다, 낮추다, 늦추다, 맞추다, 갖추다 as plain transitive verbs, exactly as you would store any vocabulary word, and keep the two traps (돋구다/돋우다, 맞추다/맞히다) on a mental sticky note.

Common Mistakes

1. Using 맞추다 for "get the answer right." That meaning belongs to 맞히다.

❌ 어려운 문제를 다 맞췄어요.

Wrong for 'got them all right' — this reads as 'compared/lined up the problems.'

✅ 어려운 문제를 다 맞혔어요.

eoryeoun munjereul da macheosseoyo

I got all the hard problems right.

2. Inventing a -추- form for "raise." 낮다 → 낮추다 ("lower"), but "raise" is not ×높추다 — it is 높이다 (a -이- verb). The suffixes do not mirror each other.

❌ 온도를 조금 높춰 주세요.

Wrong — there is no 높추다; 'raise the temperature' is 높이다.

✅ 온도를 조금 높여 주세요.

ondoreul jogeum nopyeo juseyo

Please raise the temperature a little.

3. Using 돋구다 for appetite or mood. Only glasses take 돋구다; everything else is 돋우다.

❌ 이 반찬이 입맛을 돋궈요.

Wrong — the appetite sense is 돋우다, not 돋구다.

✅ 이 반찬이 입맛을 돋워요.

i banchani immaseul dodwoyo

This side dish whets the appetite.

4. Using 갖추다 for everyday "have." 갖추다 is "be equipped/furnished with," not plain possession.

❌ 저는 차를 갖췄어요.

Odd — sounds like 'I am equipped with a car'; plain 'have' is 있다 / 가지고 있다.

✅ 저는 차가 있어요.

jeoneun chaga isseoyo

I have a car.

Key Takeaways

-구- survives in a few fossils: 달구다 (heat up), 일구다 (cultivate), 솟구다 (surge, literary), 돋구다 (glasses only).
-추- builds four degree-causatives: 낮추다 (lower), 늦추다 (delay/loosen), 맞추다 (adjust/match), 갖추다 (equip, formal).
맞추다 is high-frequency and polysemous; keep it apart from 맞히다 ("get right / hit"), the classic error.
Keep the two traps in mind: 돋구다 (glasses) vs 돋우다 (appetite/mood), and 맞추다 (align) vs 맞히다 (get right).
Neither suffix is productive — learn every -구-/-추- verb as vocabulary, and default to V-게 하다 for anything not on the list.

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