"Tushie" is a slang term that refers to a person's buttocks. There are a variety of synonyms for this word, ranging from polite to more vulgar. Some of the more acceptable synonyms include "buttocks," "rear end," "bottom," and "behind." These words are commonly used in formal or polite settings. However, more colloquial or slang synonyms include "booty," "butt," "backside," and "derriere." Other more vulgar terms for the tushie include "ass," "rump," and "bum." The use of these words can be considered vulgar or offensive in certain contexts, so it's important to be aware of your audience when using them.