WordNet (r) 3.0 (2006):

upchuck
    v 1: eject the contents of the stomach through the mouth; "After
         drinking too much, the students vomited"; "He purged
         continuously"; "The patient regurgitated the food we gave
         him last night" [syn: vomit, vomit up, purge, cast,
         sick, cat, be sick, disgorge, regorge, retch,
         puke, barf, spew, spue, chuck, upchuck, honk,
         regurgitate, throw up] [ant: keep down]

Moby Thesaurus II by Grady Ward, 1.0:

24 Moby Thesaurus words for "upchuck":
   barf, be nauseated, be seasick, be sick, bring up, choke on,
   chuck up, disgorge, egest, feed the fish, feel disgust, gag, heave,
   heave the gorge, keck, puke, regurgitate, reject, retch, sick up,
   sicken at, spew, throw up, vomit