Release one’s grip (3,2)
I believe the answer is:
let go
'release one's grip' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for let go that I've seen before include "Release - relax one's grasp" , "Give up" , "Drop" , "Set at liberty, loose grip on" , "Dismiss (from ones thoughts?)" .)