Koreans use it when something looks impressive or cool.
Yes. "멋져요 (meotjyeoyo)" is polite and common. You can also say "멋져 (meotjyeo)" casually.
You can say "That's really cool" — 정말 멋져요 (jeongmal meotjyeoyo).
멋져요 means "That's cool / stylish." 멋지다 (meotjida) = to be cool/stylish, 어요 (eoyo) = polite. Popular compliment for fashion, skills, ideas, cool actions.
1. Fashion/Skills: Cool look.
2. Ideas/Actions: Impressive.
3. Encouragement: Positive vibe.
That's cool. Did you practice a lot?
Really cool!
Really cool! (Casual)
Really cool. (Formal)
• 대박 (daebak) - Awesome
• 최고예요 (choegoyeyo) - Best
• 훌륭해요 (hullyunghaeyo) - Excellent