inflexible
intolerant
nonmoving
semirigid
unadaptable
unmoving
abiding
accurate
adamant
adamantine
at a standstill
attentive
austere
buckram
careful
cast-iron
changeless
close
conscientious
constant
continuing
correct
critical
delicate
demanding
detailed
determined
direct
dogged
dour
draconian
durable
enduring
even
exact
exacting
exigent
express
exquisite
faithful
fine
finical
finicking
finicky
firm
firm as Gibraltar
fixed
flinty
frozen
fundamentalist
fussy
grim
hard
rigor
rigour
formal
steady
stern
stiff
strict
tight
frigid
compromising
flexible
moving