Public officer’s glowing comment on periodical? (10)
I believe the answer is:
magistrate
'public officer's' is the definition.
'glowing comment on periodical?' is the wordplay.
I cannot really understand how this works, but
'on' could be 'at' (I've seen this in other clues) and 'at' is present in the answer.
'periodical?' could be 'mag' (abbreviation for magazine) and 'mag' is located in the answer.
This may be the basis of clue (or it may be nonsense).
(Other definitions for magistrate that I've seen before include "Person in court" , "Judge" , "Justice of the peace" , "Court officer" , "JP" .)