놀고 있네

you’re playing around

→ 놀다
phrase Uncommon #11,467
you’re playing around Literally means “you’re playing.” Depending on context, it can be a casual observation or a sarcastic way to say “you’re kidding” or “you must be joking.” The ending 네 expresses the speaker’s observation or reaction.
KO: 또 핑계 대고 놀고 있네!
EN: You’re making excuses again—you must be kidding!

주제에 놀고 있네

Look at you, playing around, considering your place.

— 델리카트슨 사람들 (1991)

놀고 있네

You’re just fooling around…

— 부산행 (2016)

놀고 있네

I'm playing

— 스틸 라이프 (2006)

개 랑 놀고 있네

You're playing with the dog.

— 엘리펀트 (2003)

놀고 있네!

You're playing!

— 증오 (1995)