Becomes more rigid (8)
I believe the answer is:
stiffens
(Other definitions for stiffens that I've seen before include "Goes rigid" , "gets harder" , "Tenses up" , "Braces" , "becomes hardened" .)
I believe the answer is:
stiffens
(Other definitions for stiffens that I've seen before include "Goes rigid" , "gets harder" , "Tenses up" , "Braces" , "becomes hardened" .)