pledger vs worker

pledger and worker both are nouns.

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

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

Other hypernyms of pledger include actor, doer.

pledger (noun)	worker (noun)
someone who makes or gives a pledge	sterile member of a colony of social insects that forages for food and cares for the larvae
	a person who works at a specific occupation
	a member of the working class (not necessarily employed)
	a person who acts and gets things done