tyrant vs doer

tyrant and doer both are nouns.

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

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

Other hypernyms of tyrant include actor, worker.

tyrant (noun)	doer (noun)
a cruel and oppressive dictator	a person who acts and gets things done
any person who exercises power in a cruel way
in ancient Greece, a ruler who had seized power without legal right to it