Verbseoul.
ㅂ irregular (adj)
무겁다mugeopdato be heavy

To say to be heavy politely in the present tense, use 무거워요 (moo-guh-wuh-yoh). Below is the full conjugation of 무겁다 across the three tenses and three everyday speech levels.

Conjugation table

TenseCasual (반말)Polite (요)Formal (합니다)
Present
무거워
moo-guh-wuh
무거워요
moo-guh-wuh-yoh
무겁습니다
moo-guhp-sseum-nee-dah
Past
무거웠어
moo-guh-wuh-ssuh
무거웠어요
moo-guh-wuh-ssuh-yoh
무거웠습니다
moo-guh-wuh-sseum-nee-dah
Future
무거울 거야
moo-guh-ool- -guh-yah
무거울 거예요
moo-guh-ool- -guh-yae-yoh
무거울 겁니다
moo-guh-ool- -guhm-nee-dah

Other useful forms

Command Polite (세요)
무거우세요
moo-guh-oo-sae-yoh
Suggestion / Let's Polite (요)
무거워요
moo-guh-wuh-yoh
Question Polite (요)
무거워요?
moo-guh-wuh-yoh-?
Connective “and” — (고)
무겁고
moo-guhp-goh
Conditional “if” — (면)
무거우면
moo-guh-oo-myuhn
Noun form — (기)
무거움
moo-guh-oom