pledger vs doer

pledger and doer both are nouns.

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

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

Other hypernyms of pledger include actor, worker.

pledger (noun)	doer (noun)
someone who makes or gives a pledge	a person who acts and gets things done