1. What does it mean?
존잘 abbreviates 존나 잘생겼다, roughly 'really damn good-looking.' It is an emphatic casual compliment about appearance, often in fan comments or excited reactions to photographs.
Also written or said as 존잘이다, jonjal
2. The nuance
The shortened form may feel lighter than the full phrase, but 존나 is profanity. Use it cautiously outside close, informal settings; a plain 잘생겼다 is less coarse.
3. Examples
“새 프로필 사진 보고 친구가 존잘이라고 하더라.”
My friend saw the new profile photo and said I looked ridiculously handsome.
“격식 있는 자리에서는 존잘 말고 멋지다고 표현했어.”
In a formal setting, I said someone looked great instead of using the coarse slang compliment.
Sources
Sinjoeo Korean Slang Dictionary
References support the meaning and usage. Example sentences are written for NoCapWiki.