A simp is a person who extremely expresses their feelings towards another person. Unlike caring for someone they go out of their way to get atleast 1 second of attention from the person they simp. Some of them would literally sell their liver to donate to them to get attention (as an example), and they would possibly defend them for doing something like destroying earth or something like that.
Person 1: "Yooooo, I just gave -insert person they simp- a house, a planet, the solar system, the universe, and my life!!!! I hope they notice me!!1!!1!1!1!"
Person 2: "bro. stop simping"