A saint out and about, like his adversary? (7)
I believe the answer is:
satanic
'his adversary' is the definition.
The answer and definition are not the same part of speech.
'a saint out and about' is the wordplay.
'out' indicates an anagram (out can mean wrong or inaccurate).
'and' is a charade indicator (letters next to each other).
'about' becomes 'c' (abbreviation for 'circa'**).
'a'+'saint'='asaint'
'asaint' is an anagram of 'satani'.
'satani'+'c'='SATANIC'
'like' is the link.
(Other definitions for satanic that I've seen before include "Relating to the devil" , "Diabolic" , "Bad" , "Diabolical" , "Demonic" .)