Definition from Wiktionary, the free dictionary
SWIM (third-person singular)
- Someone who isn't me; someone who isn't myself
- SWIM stole candy from the local store.
- The initialism is used such that it is grammatically identical to a third person pronoun of unspecified gender, even though in meaning it may be substituting for a first person pronoun. Mostly used to talk about something without assigning themselves blame.