cutter t-shirt
n.— «Levine recalled a teen patient from a middle-class family. She was wearing what is known as a “cutter t-shirt,” a long-sleeve t-shirt with a hole cut into the end of the sleeve to slip over the thumb and hide self-inflicted cutting on her arm.» —“Parents, beware: Affluent kids are at risk” by Bill Stanczykiewicz Indianapolis Star (Indiana) Oct. 7, 2008. (source: Double-Tongued Dictionary)