Compassion? Mine’s ending in empathy (4)
I believe the answer is:
pity
'compassion?' is the definition.
(pity is a kind of compassion)
'mine's ending in empathy' is the wordplay.
'mine' becomes 'pit' (down the pit**).
'ending in' indicates one should take the final letters.
The final letter of 'empathy' is 'y'.
'pit'+'y'='PITY'
(Other definitions for pity that I've seen before include "Crying shame" , "Cause for regret" , "Have sympathetic feelings toward" , "Sorrow for the misfortunes of others" , "true compassion?" .)