Energetic-sounding insects primarily tormenting large antelope (10)
I believe the answer is:
hartebeest
'large antelope' is the definition.
'energetic-sounding insects primarily tormenting' is the wordplay.
I cannot quite understand how this works, but
'insects' could be 'bees' (bee is a kind of insect) and 'bees' is found in the answer.
This explanation may well be incorrect...
(Other definitions for hartebeest that I've seen before include "wild animal" , "African native" , "antelope" , "Game" , "Creature" .)