1. What does it mean?
톤그로 blends tone with 어그로, attention-baiting or aggro. In beauty and styling talk it describes a makeup or clothing color that seems conspicuously out of harmony with the rest of someone's look.
Also written or said as tongeuro
2. The nuance
The judgment is subjective and can sound unkind when directed at another person. A deliberate contrast is not automatically a mistake, and personal-color labels are not compulsory rules.
3. Examples
“사진에서는 립 색만 너무 튀어서 톤그로처럼 보였어.”
In the photo, only my lip color stood out, making it look awkwardly mismatched.
“나는 마음에 드는데 친구는 톤그로라고 하더라.”
I liked the color, but my friend thought it clashed.
Sources
References support the meaning and usage. Example sentences are written for NoCapWiki.