gasp

from The American Heritage® Dictionary of the English Language, 5th Edition.

• intransitive verb To draw in the breath sharply, as from shock.
• intransitive verb To breathe convulsively or laboriously.
• intransitive verb To utter in a breathless manner.
• noun A short convulsive intake or catching of the breath.

from The Century Dictionary.

• noun The act of catching the breath with open mouth; labored respiration; a short, convulsive catching of the breath.
• To labor for breath with open mouth; respire convulsively; pant with great effort.
• To desire with eagerness; crave vehemently.
• To emit or utter gaspingly: with away, forth, out, etc.

from the GNU version of the Collaborative International Dictionary of English.

• intransitive verb To open the mouth wide in catching the breath, or in laborious respiration; to labor for breath; to respire convulsively; to pant violently.
• intransitive verb To pant with eagerness; to show vehement desire.
• transitive verb To emit or utter with gasps; -- with forth, out, away, etc.
• noun The act of opening the mouth convulsively to catch the breath; a labored respiration; a painful catching of the breath.
• noun at the point of death.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A short, sudden intake of breath.
• noun UK (slang): A draw or drag on a cigarette (or gasper).
• verb intransitive : To draw in the breath suddenly, as if from a shock.
• verb intransitive : To breathe laboriously or convulsively.
• verb transitive : To speak in a breathless manner

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a short labored intake of breath with the mouth open
• verb breathe noisily, as when one is exhausted