Understanding, not initially harsh (7)
I believe the answer is:
rasping
'harsh' is the definition.
(synonyms)
'understanding not initially' is the wordplay.
'understanding' becomes 'grasping' (to grasp something is to understand it).
'not initially' means to remove the first letter.
'grasping' with its first letter taken off is 'RASPING'.
(Other definitions for rasping that I've seen before include "Harsh" , "Making a grating noise" , "Grating harshly" .)