The Collaborative International Dictionary of English v.0.48:

Vomiting \Vom"it*ing\, n.
   The spasmodic ejection of matter from the stomach through the
   mouth.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Vomit \Vom"it\, v. i. [imp. & p. p. Vomited; p. pr. & vb. n.
   Vomiting.] [Cf. L. vomere, vomitum, and v. freq. vomitare.
   See Vomit, n.]
   To eject the contents of the stomach by the mouth; to puke;
   to spew.
   [1913 Webster]

WordNet (r) 3.0 (2006):

vomiting
    n 1: the reflex act of ejecting the contents of the stomach
         through the mouth [syn: vomit, vomiting, emesis,
         regurgitation, disgorgement, puking]

Moby Thesaurus II by Grady Ward, 1.0:

93 Moby Thesaurus words for "vomiting":
   abscess, ague, airsickness, anemia, ankylosis, anoxia, apnea,
   asphyxiation, asthma, ataxia, atrophy, backache, barf, bleeding,
   blennorhea, cachexia, cachexy, car sickness, chill, chills, colic,
   constipation, convulsion, coughing, cyanosis, diarrhea,
   disgorgement, dizziness, dropsy, dysentery, dyspepsia, dyspnea,
   edema, egesta, egestion, emaciation, fainting, fatigue, fever,
   fibrillation, flux, gagging, growth, heaves, heaving, hemorrhage,
   high blood pressure, hydrops, hypertension, hypotension, icterus,
   indigestion, inflammation, insomnia, itching, jaundice,
   labored breathing, low blood pressure, lumbago, mal de mer,
   marasmus, motion sickness, nasal discharge, nausea, necrosis, pain,
   paralysis, pruritus, puke, qualm, qualmishness, queasiness, rash,
   regurgitation, rheum, sclerosis, seasickness, seizure, shock,
   skin eruption, sneezing, sore, spasm, spew, squeamishness, tabes,
   tachycardia, tumor, upset stomach, vertigo, vomit, vomition,
   wasting