Drunken Mary traps old civic leader (5)
I believe the answer is:
mayor
'civic leader' is the definition.
(I've seen this before)
'drunken mary traps old' is the wordplay.
'drunken' indicates anagramming the letters.
'traps' indicates putting letters inside.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'mary' anagrammed gives 'mayr'.
'mayr' going around 'o' is 'MAYOR'.
(Other definitions for mayor that I've seen before include "Local bigwig" , "City leader" , "Town's chief citizen." , "Chief magistrate" , "Town's ceremonial head" .)