An instant is gripping before it may end in hatred (9)
I believe the answer is:
animosity
'hatred' is the definition.
(animosity is a kind of hatred)
'an instant is gripping before it may end' is the wordplay.
'instant' becomes 'mo' ().
'gripping' indicates putting letters inside (inserted letters are gripped).
'before' means one lot of letters go next to another.
'end' says to take the final letters.
The last letter of 'may' is 'y'.
'mo' inserted into 'is' is 'imos'.
'an'+'imos'+'it'+'y'='ANIMOSITY'
'in' is the link.
(Other definitions for animosity that I've seen before include "Maoist yin generates spirit of hostility" , "Is no amity in rancour" , "Ill-will" , "Strong hostility" , "Hostile feeling" .)