Those ending on safari, epic game reserve (3)
I believe the answer is:
ice
'reserve' is the definition.
(both can mean aloofness)
'those ending on safari epic game' is the wordplay.
'those ending on' says to take the final letters (the letters that end the words).
The final letters of 'safari epic game' are 'ICE'.
(Other definitions for ice that I've seen before include "Cool down" , "Winter formation" , "Diamonds (slang)" , "engine" , "Reserve" .)