Verbseoul.
descriptive
헛되다heotdoedavain, fruitless

To say vain, fruitless politely in the present tense, use 헛돼요 (huh-ttwae-yoh). Below is the full conjugation of 헛되다 across the three tenses and three everyday speech levels.

Conjugation table

TenseCasual (반말)Polite (요)Formal (합니다)
Present
헛돼
huh-ttwae
헛돼요
huh-ttwae-yoh
헛됩니다
huh-ttwaem-nee-dah
Past
헛됐어
huh-ttwae-ssuh
헛됐어요
huh-ttwae-ssuh-yoh
헛됐습니다
huh-ttwae-sseum-nee-dah
Future
헛될 거야
huh-ttwael- -guh-yah
헛될 거예요
huh-ttwael- -guh-yae-yoh
헛될 겁니다
huh-ttwael- -guhm-nee-dah

Other useful forms

Command Polite (세요)
헛되세요
huh-ttwae-sae-yoh
Suggestion / Let's Polite (요)
헛돼요
huh-ttwae-yoh
Question Polite (요)
헛돼요?
huh-ttwae-yoh-?
Connective “and” — (고)
헛되고
huh-ttwae-goh
Conditional “if” — (면)
헛되면
huh-ttwae-myuhn
Noun form — (기)
헛됨
huh-ttwaem