Flinches or smiles, e.g. (6)
I believe the answer is:
reacts
(Other definitions for reacts that I've seen before include "Acts in response to something" , "Responds to an impulse" , "Retaliates" , "Responds to stimulus (6)" .)
I believe the answer is:
reacts
(Other definitions for reacts that I've seen before include "Acts in response to something" , "Responds to an impulse" , "Retaliates" , "Responds to stimulus (6)" .)