A domesticated pig, especially a castrated male reared for slaughter; often taken as a type of undiscriminating greed. The word is recorded from Old English (in form hogg, hocg), perhaps of Celtic origin and related to Welsh hwch and Cornish hoch ‘pig, sow’.
go the whole hog in informal usage, do something completely or thoroughly; of several origins suggested, one interprets hog as the American slang term for a ten cent piece; another refers the idiom to one of William Cowper's poems (1779), which discusses Muslim uncertainty about which parts of the pig are acceptable as food, leading to the ‘whole hog’ being eaten, because of confusion over Muhammad's teaching.
live high on the hog in North American informal usage, have a luxurious lifestyle.
See also the cat, the rat, and Lovell our dog, Rule all England under the hog, every hog has its Martinmas.