surmounter vs restrainer

surmounter and restrainer both are nouns.

Word	Noun	Adjective	Verb	Adverb
surmounter	Yes	No	No	No
restrainer	Yes	No	No	No

As nouns, restrainer is a hypernym of surmounter; that is, restrainer is a word with a broader meaning than surmounter:

surmounter: someone who overcomes and establishes ascendancy and control by force or persuasion
restrainer: a person who directs and restrains

Other hypernyms of surmounter include controller.

surmounter (noun)	restrainer (noun)
someone who overcomes and establishes ascendancy and control by force or persuasion	a person who directs and restrains
	a chemical that is added to a photographic developer in order to retard development and reduce the amount of fog on a film