obligatory
absolute
binding
choiceless
coactive
compelling
compulsatory
compulsive
conclusive
constraining
decisive
decretory
dictated
driving
entailed
exigent
final
hard-and-fast
imperative
imperious
importunate
imposed
inevitable
involuntary
irresistible
irrevocable
mandated
mandatory
must
necessary
necessitous
peremptory
prescript
prescriptive
pressing
required
restraining
ultimate
urgent
without appeal
without choice
consequent
federal
legislative
penal
perpetual
self-imposed
strict
subsequent
temporary
unlimited
voluntary
optional