apprehender vs doer

apprehender and doer both are nouns.

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

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

apprehender: a person who seizes or arrests (especially a person who seizes or arrests in the name of justice)
doer: a person who acts and gets things done

Other hypernyms of apprehender include actor, worker.

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

Other hypernyms of apprehender include actor, worker.

apprehender (noun)	doer (noun)
a person who seizes or arrests (especially a person who seizes or arrests in the name of justice)	a person who acts and gets things done
a person who knows or apprehends