overconfidence vs certainty

overconfidence and certainty both are nouns.

Word	Noun	Adjective	Verb	Adverb
overconfidence	Yes	No	No	No
certainty	Yes	No	No	No

As nouns, certainty is a hypernym of overconfidence; that is, certainty is a word with a broader meaning than overconfidence:

overconfidence: total certainty or greater certainty than circumstances warrant
certainty: the state of being certain

overconfidence (noun)	certainty (noun)
total certainty or greater certainty than circumstances warrant	something that is certain
	the state of being certain