The Collaborative International Dictionary of English v.0.48:

evaluator \evaluator\ n.
   an authority who is able to estimate worth or quality; an
   appraiser.

   Syn: judge; appraiser.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

evaluator
    n 1: an authority who is able to estimate worth or quality [syn:
         evaluator, judge]

The Free On-line Dictionary of Computing (30 December 2018):

evaluator

    Geoff Burn defines evaluators E0, E1, E2 and E3 which
   when applied to an expression, reduce it to varying degrees.
   E0 does no evaluation, E1 it evaluates to weak head normal
   form (WHNF), E2 evaluates the structure of a list, i.e. it
   evaluates it either to NIL or evaluates it to a CONS and then
   applies E2 to the second argument of the CONS.  E3 evaluates
   the structure of a list and evaluates each element of the list
   to WHNF.  This concept can be extended to data structures
   other than lists and forms the basis of the evaluation
   transformer style of strictness analysis.

   (1994-12-12)