Verbseoul.
하다 verb (adj)
유독하다yudokhadapoisonous

To say poisonous politely in the present tense, use 유독해요 (yoo-doh-kae-yoh). Below is the full conjugation of 유독하다 across the three tenses and three everyday speech levels.

Conjugation table

TenseCasual (반말)Polite (요)Formal (합니다)
Present
유독해
yoo-doh-kae
유독해요
yoo-doh-kae-yoh
유독합니다
yoo-doh-kahm-nee-dah
Past
유독했어
yoo-doh-kae-ssuh
유독했어요
yoo-doh-kae-ssuh-yoh
유독했습니다
yoo-doh-kae-sseum-nee-dah
Future
유독할 거야
yoo-doh-kahl- -guh-yah
유독할 거예요
yoo-doh-kahl- -guh-yae-yoh
유독할 겁니다
yoo-doh-kahl- -guhm-nee-dah

Other useful forms

Command Polite (세요)
유독하세요
yoo-doh-kah-sae-yoh
Suggestion / Let's Polite (요)
유독해요
yoo-doh-kae-yoh
Question Polite (요)
유독해요?
yoo-doh-kae-yoh-?
Connective “and” — (고)
유독하고
yoo-doh-kah-goh
Conditional “if” — (면)
유독하면
yoo-doh-kah-myuhn
Noun form — (기)
유독함
yoo-doh-kahm