dismiss vs discredit

dismiss is not a noun while discredit is a noun.

Word	Noun	Adjective	Verb	Adverb
dismiss	No	No	Yes	No
discredit	Yes	No	Yes	No

As verbs, discredit is a hyponym of dismiss; that is, discredit is a word with a more specific, narrower meaning than dismiss:

dismiss (noun)	discredit (noun)
	the state of being held in low esteem

dismiss (verb)	discredit (verb)
declare void	reject as false; refuse to accept
bar from attention or consideration	cause to be distrusted or disbelieved
end one's encounter with somebody by causing or permitting the person to leave	damage the reputation of
cease to consider; put out of judicial consideration
terminate the employment of; discharge from an office or position
stop associating with