estimate vs estimator

estimate and estimator both are nouns.

Word	Noun	Adjective	Verb	Adverb
estimate	Yes	No	Yes	No
estimator	Yes	No	No	No

estimate (noun)	estimator (noun)
a judgment of the qualities of something or somebody	an expert at calculation (or at operating calculating machines)
an approximate calculation of quantity or degree or worth
the respect with which a person is held
a document appraising the value of something (as for insurance or taxation)
a statement indicating the likely cost of some job

estimate (verb)	estimator (verb)
judge tentatively or form an estimate of (quantities or time)
judge to be probable