Spanish for 'cat'. At least in Argentina (can't speak for any other country) it is used:
1. For a female, meaning 'slut' or 'whore'.
2. Less commonly, males of a lower income (the "villeros") use it to call one another.
Mirá, mirá como saca culo! ¡Que gato! ("Look at her wriggling her butt! What a cat!")