close in vs swallow

close in is not a noun while swallow is a noun.

Word	Noun	Adjective	Verb	Adverb
close in	No	No	Yes	No
swallow	Yes	No	Yes	No

As verbs, swallow is a hyponym of close in; that is, swallow is a word with a more specific, narrower meaning than close in:

close in (noun)	swallow (noun)
	the act of swallowing
	small long-winged songbird noted for swift graceful flight and the regularity of its migrations
	a small amount of liquid food

close in (verb)	swallow (verb)
surround completely	believe or accept without questioning or challenge
advance or converge on	keep from expressing
	tolerate or accommodate oneself to
	take back what one has said
	utter unclearly
	engulf and destroy
	pass through the esophagus as part of eating or drinking
	enclose or envelop completely, as if by swallowing