Senor OK playing a game (7)
I believe the answer is:
snooker
'a game' is the definition.
(snooker is a kind of game)
'senor ok playing' is the wordplay.
'playing' indicates anagramming the letters.
'senor'+'ok'='senorok'
'senorok' anagrammed gives 'SNOOKER'.
(Other definitions for snooker that I've seen before include "Stymie" , "Indoor ball game" , "Game played on a billiards table" , "check?" , "Tabletop game" .)