one who or that which acts or does: improvisator
Origin of -atorMiddle English -atour from Old French from Classical Latin -ator: see -ate and -or
One that acts in a specified manner: radiator.
Origin of -atorLatin -ātor -ā- stem vowel of verbs in -āre -tor agent n. suff. ( later reanalyzed as -ātus -ate ) ( -or -or )