The Collaborative International Dictionary of English v.0.48:
peeing \pee"ing\ (p[=e]"[i^]ng), n. Urination; -- an informal term; as, he doesn't like peeing out of doors. [Inform.] Syn: pee, pissing, urinating. [WordNet 1.5]WordNet (r) 3.0 (2006):
peeing n 1: informal terms for urination; "he took a pee" [syn: peeing, pee, pissing, piss]