Nonspeaking performer (4)
'nonspeaking performer' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for mime that I've seen before include "Dumb-show" , "Silently act out" , "Imitate without words" , "Tell a story through body movements" , "Theatrical technique" .)
(Another definition for pantomimist that I've seen is " Sort of comedy writer".)