Caught playing a foul game in disguise (10)
I believe the answer is:
camouflage
'disguise' is the definition.
(I know that camouflage is a more specific form of the action disguise)
'caught playing a foul game' is the wordplay.
'caught' becomes 'c' (cricket abbreviation).
'playing' is an anagram indicator.
'a'+'foul'+'game'='afoulgame'
'afoulgame' with letters rearranged gives 'amouflage'.
'c'+'amouflage'='CAMOUFLAGE'
'in' acts as a link.
(Other definitions for camouflage that I've seen before include "Method of blending in fine" , "blind" , "Means of disguise" , "Green and brown on a green and brown background, say?" , "Disguise (from enemy)" .)