flagging vs collection

flagging and collection both are nouns.

Word	Noun	Adjective	Verb	Adverb
flagging	Yes	Yes	No	No
collection	Yes	No	No	No

As nouns, collection is a hypernym of flagging; that is, collection is a word with a broader meaning than flagging:

Other hypernyms of flagging include accumulation, aggregation, assemblage.

flagging (noun)	collection (noun)
a walk of flagstones	the act of gathering something together
flagstones collectively	a publication containing a variety of works
	request for a sum of money
	several things grouped together or considered as a whole

flagging (adjective)	collection (adjective)
weak from exhaustion