1. What does it mean?
여친룩 joins 여친, girlfriend, and look. It is a fashion-content label for approachable, put-together outfits presented as suitable for casual dates or everyday outings. The exact clothes vary with the person and the post.
Also written or said as yeochilluk
2. The nuance
The label does not describe relationship status or a universal preference. It is a loosely gendered marketing and styling term, not a restriction on who may wear the clothes.
3. Examples
“여친룩 추천 글에서 편한 가디건 코디를 찾았어.”
I found a comfortable cardigan outfit in a girlfriend-look styling post.
“이 여친룩은 치마 대신 청바지를 매치했네.”
This girlfriend-style outfit pairs the top with jeans instead of a skirt.
Sources
References support the meaning and usage. Example sentences are written for NoCapWiki.