fly the coop vs bunk

fly the coop is not a noun while bunk is a noun.

Word	Noun	Adjective	Verb	Adverb
fly the coop	No	No	Yes	No
bunk	Yes	No	Yes	No

As verbs, fly the coop and bunk are synonyms defined as:

fly the coop (noun)	bunk (noun)
	a bed on a ship or train; usually in tiers
	a rough bed (as at a campsite)
	beds built one above the other
	a long trough for feeding cattle
	unacceptable behavior (especially ludicrously false statements)
	a message that seems to convey no meaning

fly the coop (verb)	bunk (verb)
flee; take to one's heels; cut and run	flee; take to one's heels; cut and run
	provide with a bunk
	avoid paying