A man who creeps upon girls with the intention that his actions are normal. These guys generally think they possess a huge amount of knowledge pertaining to the philosophy of love and life.
Way to physically identify a nutsack:
-Owns a personal grooming kit. This includes, but is not limited to: tweezers, nail clippers, nail file and chapstick.
-Wears ugly leather dress shoes with jeans, graphic tees, and velour blazers on a daily basis.
-Has a slimey smile.
"Hey did you hear that a guy in my fraternity followed a girl around campus yesterday"
"Yeah, he's such a nutsack."