Stimulus to action (4)
I believe the answer is:
spur
(Other definitions for spur that I've seen before include "Strong incentive" , "Incentive; branch line" , "Hurry up" , "Rider's heel wheel" , "branch road" .)
I believe the answer is:
spur
(Other definitions for spur that I've seen before include "Strong incentive" , "Incentive; branch line" , "Hurry up" , "Rider's heel wheel" , "branch road" .)