Verbseoul.
하다 verb (adj)
능숙하다neungsukhadato be proficient, to be adept

To say to be proficient, to be adept politely in the present tense, use 능숙해요 (neung-soo-kae-yoh). Below is the full conjugation of 능숙하다 across the three tenses and three everyday speech levels.

Conjugation table

TenseCasual (반말)Polite (요)Formal (합니다)
Present
능숙해
neung-soo-kae
능숙해요
neung-soo-kae-yoh
능숙합니다
neung-soo-kahm-nee-dah
Past
능숙했어
neung-soo-kae-ssuh
능숙했어요
neung-soo-kae-ssuh-yoh
능숙했습니다
neung-soo-kae-sseum-nee-dah
Future
능숙할 거야
neung-soo-kahl- -guh-yah
능숙할 거예요
neung-soo-kahl- -guh-yae-yoh
능숙할 겁니다
neung-soo-kahl- -guhm-nee-dah

Other useful forms

Command Polite (세요)
능숙하세요
neung-soo-kah-sae-yoh
Suggestion / Let's Polite (요)
능숙해요
neung-soo-kae-yoh
Question Polite (요)
능숙해요?
neung-soo-kae-yoh-?
Connective “and” — (고)
능숙하고
neung-soo-kah-goh
Conditional “if” — (면)
능숙하면
neung-soo-kah-myuhn
Noun form — (기)
능숙함
neung-soo-kahm