Verbseoul.
하다 verb (adj)
대단하다daedanhadato be great, huge, immense, enormous, tremendous

To say to be great, huge, immense, enormous, tremendous politely in the present tense, use 대단해요 (dae-dahn-hae-yoh). Below is the full conjugation of 대단하다 across the three tenses and three everyday speech levels.

Conjugation table

TenseCasual (반말)Polite (요)Formal (합니다)
Present
대단해
dae-dahn-hae
대단해요
dae-dahn-hae-yoh
대단합니다
dae-dahn-hahm-nee-dah
Past
대단했어
dae-dahn-hae-ssuh
대단했어요
dae-dahn-hae-ssuh-yoh
대단했습니다
dae-dahn-hae-sseum-nee-dah
Future
대단할 거야
dae-dahn-hahl- -guh-yah
대단할 거예요
dae-dahn-hahl- -guh-yae-yoh
대단할 겁니다
dae-dahn-hahl- -guhm-nee-dah

Other useful forms

Command Polite (세요)
대단하세요
dae-dahn-hah-sae-yoh
Suggestion / Let's Polite (요)
대단해요
dae-dahn-hae-yoh
Question Polite (요)
대단해요?
dae-dahn-hae-yoh-?
Connective “and” — (고)
대단하고
dae-dahn-hah-goh
Conditional “if” — (면)
대단하면
dae-dahn-hah-myuhn
Noun form — (기)
대단함
dae-dahn-hahm