Being in torment, it yelps (6)
I believe the answer is:
entity
'being' is the definition.
(I've seen this in other clues)
'in torment it yelps' is the wordplay.
'in' indicates the answer is hidden within the clue.
'ENTITY' can be found hidden inside 'torment it yelps'.
(Other definitions for entity that I've seen before include "It exists as a seperate thing (6)" , "A thing with distinct and independent existence" , "Object" , "Something existing in its own right" , "Individual being" .)