collect vs stack away

collect is a noun but stack away is not a noun.

Word	Noun	Adjective	Verb	Adverb
collect	Yes	Yes	Yes	Yes
stack away	No	No	Yes	No

As verbs, stack away is a hypernym of collect; that is, stack away is a word with a broader meaning than collect:

Other hypernyms of collect include hive away, lay in, put in, salt away, stash away, store.

collect (noun)	stack away (noun)
a short prayer generally preceding the lesson in the Church of Rome or the Church of England

collect (adjective)	stack away (adjective)
payable by the recipient on delivery

collect (verb)	stack away (verb)
assemble or get together	keep or lay aside for future use
get or bring together
get or gather together
call for and obtain payment of
gather or collect

collect (adverb)	stack away (adverb)
make a telephone call or mail a package so that the recipient pays