Verbseoul.
ㅂ irregular (adj)
해롭다haeropdato be harmful

To say to be harmful politely in the present tense, use 해로워요 (hae-roh-wuh-yoh). Below is the full conjugation of 해롭다 across the three tenses and three everyday speech levels.

Conjugation table

TenseCasual (반말)Polite (요)Formal (합니다)
Present
해로워
hae-roh-wuh
해로워요
hae-roh-wuh-yoh
해롭습니다
hae-rohp-sseum-nee-dah
Past
해로웠어
hae-roh-wuh-ssuh
해로웠어요
hae-roh-wuh-ssuh-yoh
해로웠습니다
hae-roh-wuh-sseum-nee-dah
Future
해로울 거야
hae-roh-ool- -guh-yah
해로울 거예요
hae-roh-ool- -guh-yae-yoh
해로울 겁니다
hae-roh-ool- -guhm-nee-dah

Other useful forms

Command Polite (세요)
해로우세요
hae-roh-oo-sae-yoh
Suggestion / Let's Polite (요)
해로워요
hae-roh-wuh-yoh
Question Polite (요)
해로워요?
hae-roh-wuh-yoh-?
Connective “and” — (고)
해롭고
hae-rohp-goh
Conditional “if” — (면)
해로우면
hae-roh-oo-myuhn
Noun form — (기)
해로움
hae-roh-oom