1. gack - Noun
2. gack - Verb
3. gack - Interjection
(often repeated several times) A sharp, sudden sound from someone's throat while they're coughing, vomiting, gagging, etc.
An expression of disgust or disapproval.
An expression of trepidation.
(intransitive) To make a sharp, sudden sound in one's throat, such as before vomiting or while coughing, gagging, etc.
To do something that causes a sharp, sudden sound in one's throat.
(intransitive) To vomit, throw up.
(transitive) To cough something up.
(intransitive) To choke (be unable to breathe because of obstruction of the windpipe)
(intransitive) To choke (experience tightness in one's throat as a result of strong emotion)
(slang) Crystal meth.
(slang) Powder cocaine.
gack
The sound of a bird's call in response to disturbance.
gack (third-person singular simple present gacks, present participle gacking, simple past and past participle gacked)
(of a bird) To call in response to disturbance.
"Six Sigma is all about the outcomes," said Gary Gack, owner and principal consultant of Process-Fusion. Source: Internet