Give a second gesture (6)
I believe the answer is:
assign
'give' is the definition.
(I've seen this before)
'a second gesture' is the wordplay.
'second' becomes 's' (common abbreviation).
'gesture' becomes 'sign' (sign is a kind of gesture).
'a'+'s'+'sign'='ASSIGN'
(Other definitions for assign that I've seen before include "Allocate, a job say" , "award" , "Make over" , "Allot, fix, appoint" , "Set aside for a specific purpose" .)