Merriam-Webster's Collegiate® Dictionary, 11th Edition
SWILL
I. verb
Etymology: Middle English swilen, from Old English swillan Date: before 12th century transitive verb wash , drench , to drink great drafts of ; guzzle , to feed (as a pig) with swill, intransitive verb to drink or eat freely, greedily, or to excess, swash , swiller noun
II. noun
Date: 1553
something suggestive of slop or garbage ; refuse ,
2. a semiliquid food for animals (as swine) composed of edible refuse mixed with water or skimmed or sour milk, garbage