swallow vs shut in

swallow is a noun but shut in is not a noun.

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

As verbs, shut in is a hypernym of swallow; that is, shut in is a word with a broader meaning than swallow:

Other hypernyms of swallow include close in, enclose, inclose.

swallow (noun)	shut in (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

swallow (verb)	shut in (verb)
believe or accept without questioning or challenge	surround completely
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