coin collection vs collecting

coin collection and collecting both are nouns.

Word	Noun	Adjective	Verb	Adverb
coin collection	Yes	No	No	No
collecting	Yes	No	No	No

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

coin collection: the collection and study of money (and coins in particular)
collecting: the act of gathering something together

Other hypernyms of coin collection include aggregation, assembling, collection.

coin collection (noun)	collecting (noun)
the collection and study of money (and coins in particular)	the act of gathering something together
a collection of coins