Verbseoul.
하다 verb (adj)
납작하다napjakhadato be flat, thin, low

To say to be flat, thin, low politely in the present tense, use 납작해요 (nahp-chah-kae-yoh). Below is the full conjugation of 납작하다 across the three tenses and three everyday speech levels.

Conjugation table

TenseCasual (반말)Polite (요)Formal (합니다)
Present
납작해
nahp-chah-kae
납작해요
nahp-chah-kae-yoh
납작합니다
nahp-chah-kahm-nee-dah
Past
납작했어
nahp-chah-kae-ssuh
납작했어요
nahp-chah-kae-ssuh-yoh
납작했습니다
nahp-chah-kae-sseum-nee-dah
Future
납작할 거야
nahp-chah-kahl- -guh-yah
납작할 거예요
nahp-chah-kahl- -guh-yae-yoh
납작할 겁니다
nahp-chah-kahl- -guhm-nee-dah

Other useful forms

Command Polite (세요)
납작하세요
nahp-chah-kah-sae-yoh
Suggestion / Let's Polite (요)
납작해요
nahp-chah-kae-yoh
Question Polite (요)
납작해요?
nahp-chah-kae-yoh-?
Connective “and” — (고)
납작하고
nahp-chah-kah-goh
Conditional “if” — (면)
납작하면
nahp-chah-kah-myuhn
Noun form — (기)
납작함
nahp-chah-kahm