Devout old man embracing bishop (9)
I believe the answer is:
observant
'devout' is the definition.
(thesaurus)
'old man embracing bishop' is the wordplay.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'man' becomes 'servant' (man can mean someone's personal servant).
'embracing' is an insertion indicator.
'bishop' becomes 'B' (abbreviation used in chess).
'o'+'servant'='oservant'
'oservant' going around 'b' is 'OBSERVANT'.
(Other definitions for observant that I've seen before include "following religious practices" , "with a keen eye" , "Keen-eyed" , "taking things in" , "Perceptive" .)