Simp is a newer term. A lot of times it’s in reference to describe guys chasing after or worshipping females on social media online.
The earliest form of Simp were the dudes on TGG that used to give Pam a ton of extra attention because she was the only female on the board. Even though she was an anonymous, faceless, middle aged, married, and possibly a dude. She always had dude like hornet asking her questions, complimenting her, and fishing for interactions.
A lot of “simping” ive witnessed is online - guys that don’t have much interaction with females irl and are much more comfortable hitting on them or saying something outrageous from behind their keyboard.
