underestimate vs overestimate

underestimate and overestimate both are nouns.

Word	Noun	Adjective	Verb	Adverb
underestimate	Yes	No	Yes	No
overestimate	Yes	No	Yes	No

underestimate (noun)	overestimate (noun)
an estimation that is too low; an estimate that is less than the true or actual value	a calculation that results in an estimate that is too high
	an appraisal that is too high

underestimate (verb)	overestimate (verb)
make a deliberately low estimate	make too high an estimate of
make too low an estimate of	assign too high a value to
assign too low a value to