Flag identified by celebrities with priests, possibly (5,3,7)
I believe the answer is:
stars and stripes
'flag' is the definition.
(I know that Stars and Stripes is a type of flag)
'celebrities with priests possibly' is the wordplay.
'celebrities' becomes 'stars' (I've seen this in other clues).
'with' becomes 'and'.
'possibly' is an anagram indicator.
'priests' anagrammed gives 'stripes'.
'stars'+'and'+'stripes'='STARS AND STRIPES'
'identified by' acts as a link.
(Other definitions for stars and stripes that I've seen before include "American flier" , "The US flag" , "Standard" , "indicators of military rank" , "indications of rank" .)