overestimate vs overestimation

overestimate and overestimation both are nouns.

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

As nouns, overestimate and overestimation are synonyms defined as:

overestimate and overestimation: a calculation that results in an estimate that is too high

Other synonyms of overestimate include overrating, overreckoning.

As nouns, overestimate and overestimation are synonyms defined as:

Other synonyms of overestimate include overappraisal, overvaluation.

overestimate (noun)	overestimation (noun)
a calculation that results in an estimate that is too high	a calculation that results in an estimate that is too high
an appraisal that is too high	an appraisal that is too high

overestimate (verb)	overestimation (verb)
make too high an estimate of
assign too high a value to