challenger vs challenge

challenger and challenge both are nouns.

Word	Noun	Adjective	Verb	Adverb
challenger	Yes	No	No	No
challenge	Yes	No	Yes	No

challenger (noun)	challenge (noun)
the contestant you hope to defeat	a call to engage in a contest or fight
	questioning a statement and demanding an explanation
	a formal objection to the selection of a particular person as a juror
	a demand by a sentry for a password or identification
	a demanding or stimulating situation

challenger (verb)	challenge (verb)
	issue a challenge to
	take exception to
	raise a formal objection in a court of law
	ask for identification