Deceptive Doreen holding spades back (7)
I believe the answer is:
endorse
'back' is the definition.
(back can mean to support or endorse)
'deceptive doreen holding spades' is the wordplay.
'deceptive' indicates an anagram.
'holding' means one lot of letters goes inside another.
'spades' becomes 's' (abbreviation in card games).
'doreen' anagrammed gives 'endore'.
'endore' placed around 's' is 'ENDORSE'.
(Other definitions for endorse that I've seen before include "Put penalty points on (a driving licence)" , "Back, sanction" , "Docket" , "Affirm" , "Put one's name to, approve" .)