Verbseoul.
하다 verb (adj)
끔찍하다kkeumjjikhadato be terrible

To say to be terrible politely in the present tense, use 끔찍해요 (ggeum-jjee-kae-yoh). Below is the full conjugation of 끔찍하다 across the three tenses and three everyday speech levels.

Conjugation table

TenseCasual (반말)Polite (요)Formal (합니다)
Present
끔찍해
ggeum-jjee-kae
끔찍해요
ggeum-jjee-kae-yoh
끔찍합니다
ggeum-jjee-kahm-nee-dah
Past
끔찍했어
ggeum-jjee-kae-ssuh
끔찍했어요
ggeum-jjee-kae-ssuh-yoh
끔찍했습니다
ggeum-jjee-kae-sseum-nee-dah
Future
끔찍할 거야
ggeum-jjee-kahl- -guh-yah
끔찍할 거예요
ggeum-jjee-kahl- -guh-yae-yoh
끔찍할 겁니다
ggeum-jjee-kahl- -guhm-nee-dah

Other useful forms

Command Polite (세요)
끔찍하세요
ggeum-jjee-kah-sae-yoh
Suggestion / Let's Polite (요)
끔찍해요
ggeum-jjee-kae-yoh
Question Polite (요)
끔찍해요?
ggeum-jjee-kae-yoh-?
Connective “and” — (고)
끔찍하고
ggeum-jjee-kah-goh
Conditional “if” — (면)
끔찍하면
ggeum-jjee-kah-myuhn
Noun form — (기)
끔찍함
ggeum-jjee-kahm