Pontifical comrade coming round every year (5)
I believe the answer is:
papal
'pontifical' is the definition.
(thesaurus)
'comrade coming round every year' is the wordplay.
'comrade' becomes 'pal' (I've seen this in other clues).
'coming round' indicates putting letters inside.
'every year' becomes 'pa' (per annum).
'pal' placed around 'pa' is 'PAPAL'.
(Other definitions for papal that I've seen before include "Relating to the Pope" , "Of the RC leader" , "Like some bulls" , "Of the highest Vatican authority" , "of Catholic high-up" .)