Strict; rigid (9)
I believe the answer is:
stringent
I believe this clue is a double definition.
'strict' is the first definition.
(I've seen this before)
'rigid' is the second definition.
(thesaurus)
(Other definitions for stringent that I've seen before include "Harsh" , "Strict, precise, exacting" , "Demanding, inflexible" , "(Rule) allowing no discretion" , "tightly drawn" .)