swill down vs swill

swill down is not a noun while swill is a noun.

Word	Noun	Adjective	Verb	Adverb
swill down	No	No	Yes	No
swill	Yes	No	Yes	No

As verbs, swill down and swill are synonyms defined as:

swill down and swill: drink large quantities of (liquid, especially alcoholic drink)

swill down (noun)	swill (noun)
	wet feed (especially for pigs) consisting of mostly kitchen waste mixed with water or skimmed or sour milk

swill down (verb)	swill (verb)
drink large quantities of (liquid, especially alcoholic drink)	drink large quantities of (liquid, especially alcoholic drink)
	feed pigs