Adjectives · ㅂ irregular

무겁다 conjugation

to be heavy · mugeopda · sounds like [무겁따]

Short answer: “Heavy” in Korean is 무겁다 (mugeopda). Polite present: 무거워요 (mugeowoyo); past: 무거웠어요 (mugeowosseoyo); future: 무거울 거예요. It is a ㅂ irregular adjective.

Present무거워요[무거워요] · mugeowoyo
Past무거웠어요[무거워써요] · mugeowosseoyo
Future무거울 거예요[무거울 꺼예요] · mugeoul geoyeyo
Negative안 무거워요[안 무거워요] · an mugeowoyo

Opposite: 가볍다 — to be light (weight)

무겁다 in sentences

상자가 무거워요.The box is heavy.
무거운 짐은 제가 들게요.I’ll carry the heavy bags.

All forms of 무겁다

Present
Polite (해요) is the everyday safe choice; formal (합니다) is for news, announcements and work; casual (반말) is for close friends and younger people.
Form	Korean	Sounds like	Romanized
polite-아/어요	무거워요	[무거워요]	mugeowoyo
formal-(스)ㅂ니다	무겁습니다	[무겁씀니다]	mugeopseumnida
casual-아/어	무거워	[무거워]	mugeowo
plain (written)-다	무겁다	[무겁따]	mugeopda
formal question-(스)ㅂ니까?	무겁습니까?	[무겁씀니까]	mugeopseumnikka?

Past
Form	Korean	Sounds like	Romanized
polite-았/었어요	무거웠어요	[무거워써요]	mugeowosseoyo
formal-았/었습니다	무거웠습니다	[무거웓씀니다]	mugeowotseumnida
casual-았/었어	무거웠어	[무거워써]	mugeowosseo
plain (written)-았/었다	무거웠다	[무거웓따]	mugeowotda

Future
Form	Korean	Sounds like	Romanized
polite — will probably be-(으)ㄹ 거예요	무거울 거예요	[무거울 꺼예요]	mugeoul geoyeyo
formal-(으)ㄹ 겁니다	무거울 겁니다	[무거울 껌니다]	mugeoul geomnida
casual-(으)ㄹ 거야	무거울 거야	[무거울 꺼야]	mugeoul geoya

Negative
Form	Korean	Sounds like	Romanized
not (short)안 …	안 무거워요	[안 무거워요]	an mugeowoyo
did not안 …았/었어요	안 무거웠어요	[안 무거워써요]	an mugeowosseoyo
not (long)-지 않아요	무겁지 않아요	[무겁찌 아나요]	mugeopji anayo

Honorific
Add -(으)시- when the subject is someone you respect (a teacher, a customer, an older person) — not yourself.
Form	Korean	Sounds like	Romanized
honorific — present-(으)세요	무거우세요	[무거우세요]	mugeouseyo
honorific — past-(으)셨어요	무거우셨어요	[무거우셔써요]	mugeousyeosseoyo
honorific — formal-(으)십니다	무거우십니다	[무거우심니다]	mugeousimnida

Connecting
Form	Korean	Sounds like	Romanized
… and-고	무겁고	[무겁꼬]	mugeopgo
… so / and then-아/어서	무거워서	[무거워서]	mugeowoseo
if …-(으)면	무거우면	[무거우면]	mugeoumyeon
… but-지만	무겁지만	[무겁찌만]	mugeopjiman
because …-(으)니까	무거우니까	[무거우니까]	mugeounikka
… and / but (background)-(으)ㄴ데	무거운데	[무거운데]	mugeounde
even if …-아/어도	무거워도	[무거워도]	mugeowodo
while …-(으)면서	무거우면서	[무거우면서]	mugeoumyeonseo

Describing a noun
These go before a noun: “the food (that) I ate”, “a cold day”.
Form	Korean	Sounds like	Romanized
(that is) …-(으)ㄴ	무거운	[무거운]	mugeoun
(that) will …-(으)ㄹ	무거울	[무거울]	mugeoul

Useful patterns
Form	Korean	Sounds like	Romanized
can be …-(으)ㄹ 수 있어요	무거울 수 있어요	[무거울 쑤 이써요]	mugeoul su isseoyo
cannot be …-(으)ㄹ 수 없어요	무거울 수 없어요	[무거울 쑤 업써요]	mugeoul su eopseoyo
have to be …-아/어야 해요	무거워야 해요	[무거워야 해요]	mugeowoya haeyo
it’s OK if it’s …-아/어도 돼요	무거워도 돼요	[무거워도 돼요]	mugeowodo dwaeyo
…ly (adverb)-게	무겁게	[무겁께]	mugeopge
becomes …-아/어지다	무거워져요	[무거워저요]	mugeowojeoyo
…ing (noun)-기	무겁기	[무겁끼]	mugeopgi

How 무겁다 changes

ㅂ irregular: before a vowel, ㅂ turns into 우 — so 무겁 + 어 → 무거워요, and -(으) endings use 우: 무거우면, 무거울. Before a consonant the ㅂ stays: 무겁습니다, 무겁고. Not every ㅂ word does this — 입다 → 입어요 and 잡다 → 잡아요 are regular.

How every verb type works → · Why it sounds like that →

Questions

How do you say “heavy” in Korean?

“Heavy” is 무겁다 (mugeopda), pronounced [무겁따]. In a sentence: 상자가 무거워요. — The box is heavy.

What is the past tense of 무겁다?

무거웠어요 (mugeowosseoyo) is the polite past tense of 무겁다 (“to be heavy”). Formal: 무거웠습니다; casual: 무거웠어.

How do you say 무겁다 politely?

Everyday polite: 무거워요 (mugeowoyo). Formal: 무겁습니다. Casual, with close friends: 무거워.

How do you say “not heavy” in Korean?

안 무거워요 or 무겁지 않아요. Both mean the same; the first is more common in speech.

Is 무겁다 irregular?

Yes — ㅂ irregular: before a vowel, ㅂ turns into 우 — so 무겁 + 어 → 무거워요, and -(으) endings use 우: 무거우면, 무거울. Before a consonant the ㅂ stays: 무겁습니다, 무겁고. Not every ㅂ word does this — 입다 → 입어요 and 잡다 → 잡아요 are regular.

More ㅂ irregular words like 무겁다

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Forms follow 한글 맞춤법 (Korean spelling rules); pronunciation follows 표준 발음법 and romanization follows 국어의 로마자 표기법 (Revised Romanization). Last updated October 16, 2026. How we check