좋대

they say it's good, is said to be good

→ 좋다
좋 feel pleasant + 대 Reported speech (hearsay)
adjective Rare #27,248
they say it's good, is said to be good A shortened form of 좋다고 해, used to report what someone says or what is apparently true.
KO: 이 차가 감기에 좋대.
EN: They say this tea is good for a cold.
Forms of 좋다

우연히 만나는 게 좋대

They say they like running into people by chance.

— 인생은 아름다워 (1997)

인상 쓰는 게 좋대?

Is it good to make a face?

— 아멜리에 (2001)