Dictionary.net

/barf/ [mainstream slang for "vomit"] 1. Term of disgust.This is the closest hackish equivalent of the Val\-speak "gagme with a spoon". (Like, euwww!) See bletch.2. To say "Barf!" or emit some similar expression of disgust."I showed him my latest hack and he barfed" means only that hecomplained about it, not that he literally vomited.3. To fail to work because of unacceptable input, perhaps witha suitable error message, perhaps not. Examples: "Thedivision operation barfs if you try to divide by 0." (Thatis, the division operation checks for an attempt to divide byzero, and if one is encountered it causes the operation tofail in some unspecified, but generally obvious, manner.) "Thetext editor barfs if you try to read in a new file beforewriting out the old one".See choke, gag.In Commonwealth Hackish, "barf" is generally replaced by"puke" or "vom". barf is sometimes also used as ametasyntactic variable, like foo or bar.