WordNet sense 1 (make pure or free from sin or guilt):

purify, sanctify

WordNet sense 2 (rinse, clean, or empty with a liquid):

flush, scour

WordNet sense 3 (the act of clearing yourself (or another) from some stigma or charge):

purgation, purging

WordNet sense 4 (eject the contents of the stomach through the mouth):

barf, cast, cat, chuck, disgorge, honk, puke, regurgitate, retch, sick, spew, upchuck, vomit, regorge, spue, be sick, throw up, vomit up