Something said about an evangelist (6)
I believe the answer is:
remark
'something said' is the definition.
(a comment or utterance)
'about an evangelist' is the wordplay.
'about' becomes 're' ('re' means regarding or about).
'an evangelist' becomes 'mark' (traditional author of the Gospel of Mark).
're'+'mark'='REMARK'
(Other definitions for remark that I've seen before include "Something said; take notice of" , "Mention - observe" , "Notice; happen to say" , "Say as a comment" , "Written or spoken comment" .)