Granted there's many a devious deed (5)
I believe the answer is:
ceded
'granted' is the definition.
('cede' can be a synonym of 'grant')
'there's many a devious deed' is the wordplay.
'there's' is a charade indicator (letters next to each other).
'many' becomes 'c' (C is the Roman numeral for 100).
'a devious' indicates anagramming the letters.
'deed' is an anagram of 'eded'.
'c'+'eded' is 'CEDED'.
(Other definitions for ceded that I've seen before include "Gave up (power)" , "Given up" , "Conceded or gave up" , "Yielded, surrendered" , "Relinquished" .)