withholder vs controller

withholder and controller both are nouns.

Word	Noun	Adjective	Verb	Adverb
withholder	Yes	No	No	No
controller	Yes	No	No	No

As nouns, controller is a hypernym of withholder; that is, controller is a word with a broader meaning than withholder:

Other hypernyms of withholder include restrainer.

withholder (noun)	controller (noun)
a person who restrains or checks or holds back	a mechanism that controls the operation of a machine
a person who refrains from granting	someone who maintains and audits business accounts
	a person who directs and restrains