sniffer vs doer

sniffer and doer both are nouns.

Word	Noun	Adjective	Verb	Adverb
sniffer	Yes	No	No	No
doer	Yes	No	No	No

As nouns, doer is a hypernym of sniffer; that is, doer is a word with a broader meaning than sniffer:

Other hypernyms of sniffer include actor, worker.

sniffer (noun)	doer (noun)
a person who sniffs	a person who acts and gets things done