waiter vs doer

waiter and doer both are nouns.

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

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

Other hypernyms of waiter include actor, worker.

waiter (noun)	doer (noun)
a person whose occupation is to serve at table (as in a restaurant)	a person who acts and gets things done
a person who waits or awaits