witness vs discover

witness is a noun but discover is not a noun.

Word	Noun	Adjective	Verb	Adverb
witness	Yes	No	Yes	No
discover	No	No	Yes	No

witness (noun)	discover (noun)
testimony by word or deed to your religious faith
someone who sees an event and reports what happened
a close observer; someone who looks at something (such as an exhibition of some kind)
(law) a person who attests to the genuineness of a document or signature by adding their own signature
(law) a person who testifies under oath in a court of law

witness (verb)	discover (verb)
be a witness to	get to know or become aware of, usually accidentally
perceive or be contemporaneous with	identify as in botany or biology, for example
	make known to the public information that was previously known only to a few people or that was meant to be kept a secret
	make a discovery, make a new finding
	see for the first time; make a discovery
	discover or determine the existence, presence, or fact of by perception with the eyes
	find unexpectedly