Almost stop ruler after game? (8)
I believe the answer is:
stalking
'after game?' is the definition.
(I've seen this before)
'almost stop ruler' is the wordplay.
'almost' means to remove the last letter (most of the word but not all of it).
'stop' becomes 'stall' (stalling is a kind of stopping).
'ruler' becomes 'king' (king is a kind of ruler).
'stall' with its last letter removed is 'stal'.
'stal'+'king'='STALKING'
(Other definitions for stalking that I've seen before include "Following stealthily" , "Carefully following" , "After game" , "providing unwanted attention?" , "Covertly following" .)