An overly sympathetic being towards feelings and desires in which the energy isn’t reciprocated.
General Respect and common courtesy does’t necessarily relate to becoming a SIMP.
John leaves his work to bring Isabella lunch daily. He leaves her a note everyday telling her something he enjoys about her. Isabella pays the note little to no mind, and simply thanks him in a text. This alone motivates John to continuously keep bringing her lunch. Meanwhile, he is taking unnecessary breaks giving her attention and energy which isn’t being returned. John is a SIMP.
Simp is a slang insult for men who are seen as too attentive and submissive to women, especially out of a failed hope of winning some entitled sexual attention or activity from them. Translation? The word simp is meant to troll young men for doing anything for a girl to get some action he supposedly deserves.