WordNet (r) 3.0 (2006):

hiccup
    n 1: (usually plural) the state of having reflex spasms of the
         diaphragm accompanied by a rapid closure of the glottis
         producing an audible sound; sometimes a symptom of
         indigestion; "how do you cure the hiccups?" [syn: hiccup,
         hiccough, singultus]
    v 1: breathe spasmodically, and make a sound; "When you have to
         hiccup, drink a glass of cold water" [syn: hiccup,
         hiccough]

Moby Thesaurus II by Grady Ward, 1.0:

60 Moby Thesaurus words for "hiccup":
   Aqua-Lung, artificial respiration, aspiration, asthmatic wheeze,
   belch, blow, breath, breath of air, breathe, breathe hard,
   breathe in, breathe out, breathing, broken wind, burp, cough,
   eruct, eructate, eructation, exhalation, exhale, exhaust, expel,
   expiration, expire, exsufflation, gas, gasp, gulp, hack, huff,
   inhalation, inhalator, inhale, inspiration, inspire, insufflation,
   iron lung, mouth-to-mouth resuscitation, oxygen mask, oxygen tent,
   pant, puff, respiration, respire, scuba, sigh, sneeze, sniff,
   sniffle, snore, snoring, snort, snuff, snuffle, sternutation,
   stertor, suspiration, wheeze, wind