Barf/bɑːrf/ Definition 1 of 3Pro Tip 1/3Informal Usage Use 'barf' in casual situations or with friends, not in formal contexts. I can't eat anymore, or I'll barf. Pro Tip 2/3Physical Reaction 'Barf' specifically describes the act of vomiting, usually suddenly and violently. The turbulent flight made half the passengers barf. Pro Tip 3/3Humor or Sarcasm Sometimes 'barf' is used humorously or sarcastically to exaggerate discomfort. If I have to hear that song again, I'm gonna barf.