(jargon) (MIT) 1. To fail. A program loses when it encounters an exceptional condition or fails to work in the expected manner.
2. To be exceptionally unesthetic or crocky. 3. Of people, to be obnoxious or unusually stupid (as opposed to ignorant). 4. Refers to something that is losing, especially in the phrases "That's a lose!" and "What a lose!" [Jargon File]