computer vs estimator

computer and estimator both are nouns.

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

As nouns, computer and estimator are synonyms defined as:

computer and estimator: an expert at calculation (or at operating calculating machines)

Other synonyms of computer include calculator, figurer, reckoner.

computer (noun)	estimator (noun)
a machine for performing calculations automatically	an expert at calculation (or at operating calculating machines)
an expert at calculation (or at operating calculating machines)