Verbseoul.
ㄷ irregular
붇다butda-2to swell up

To say to swell up politely in the present tense, use 불어요 (boo-ruh-yoh). Below is the full conjugation of 붇다 across the three tenses and three everyday speech levels.

Conjugation table

TenseCasual (반말)Polite (요)Formal (합니다)
Present
불어
boo-ruh
불어요
boo-ruh-yoh
붇습니다
boot-seum-nee-dah
Past
불었어
boo-ruh-ssuh
불었어요
boo-ruh-ssuh-yoh
불었습니다
boo-ruh-sseum-nee-dah
Future
불을 거야
boo-reul- -guh-yah
불을 거예요
boo-reul- -guh-yae-yoh
불을 겁니다
boo-reul- -guhm-nee-dah

Other useful forms

Command Polite (세요)
불으세요
boo-reu-sae-yoh
Suggestion / Let's Polite (요)
불어요
boo-ruh-yoh
Question Polite (요)
불어요?
boo-ruh-yoh-?
Connective “and” — (고)
붇고
boot-goh
Conditional “if” — (면)
불으면
boo-reu-myuhn
Noun form — (기)
불음
boo-reum