commentator
NounWordNet 3.0
Webster's Dictionary (GCIDE)
Commentator \Com"men*ta`tor\, n. [L. commentator: cf. F. commentateur.] One who writes a commentary or comments; an expositor; an annotator. [1913 Webster]
The commentator's professed object is to explain, to enforce, to illustrate doctrines claimed as true. --Whewell. [1913 Webster]