Spades cut in dull card game (5)
I believe the answer is:
ombre
'card game' is the definition.
(I've seen this before)
'spades cut in dull' is the wordplay.
'spades' becomes 's' (abbreviation in card games).
'cut in' is a deletion indicator.
'dull' becomes 'sombre'.
'sombre' with 's' removed is 'OMBRE'.
(Other definitions for ombre that I've seen before include "Shaded" , "Game using 40 cards" , "Three-player card game" , "- Stravinsky, composer" , "Card game, the name derived from the Spanish for man" .)