Rigid; severe (5)
I believe the answer is:
stiff
I believe this is a double definition.
'rigid' is the first definition.
(I know that rigid can be written as stiff)
'severe' is the second definition.
(thesaurus)
(Other definitions for stiff that I've seen before include "Inflexible" , "Rigid, prim" , "Not easily bent" , "cheat" , "Rigid, unbending" .)