A "simp" is a slang term used to describe a person who is perceived as overly submissive or even desperate for the attention or affection of someone without receiving anything in return. The term is often used in a derogatory way to shame or criticize individuals who are seen as putting in too much effort to impress or gain favor with someone who is not reciprocating their feelings or actions. The term has been used since the early 2000s, but its meaning has evolved over time. It has been expressed as a backronym for "Sucker/Sucka Idolizing Mediocre Pussy," which according to Gizmodo Australia is "telling of its 20th century origins". The term has been adopted by members of manosphere, incel, and MGTOW (Men Going Their Own Way) forums alongside similar derogatory terms such as cuck, beta, and white knight.

The term "simp" has achieved broad popularity and has been used more loosely. In April 2020, an opinion piece in Mens Health described the use of the term as "pretty messed up," and men who labeled others with the term as "entitled assholes," saying, "if youve ever complimented a woman, apparently youre a simp".

In summary, a "simp" is a term used to describe someone who shows excessive sympathy and attention toward another person, typically someone who does not reciprocate the same feelings, in pursuit of affection or a sexual relationship.