Nonverbal approval (3)
I believe the answer is:
nod
'nonverbal approval' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for nod that I've seen before include "Doze" , "Asleep in the land" , "Where Cain went to" , "Signify agreement" , "'A . . . is as good as a wink to a blind horse'" .)