dead
nonresilient
springless
adamant
adamantine
cast-iron
dour
firm
flinty
grim
hard
hard-core
immovable
immutable
implacable
impliable
inductile
inexorable
inextensible
inextensile
inextensional
inflexible
intractable
intractile
intransigent
iron
irreconcilable
irresilient
nonelastic
nonstretchable
plastic
relentless
rigid
rigorous
rock-ribbed
steely
stern
stiff
stubborn
unaffected
unalterable
unbending
unchangeable
uncompromising
unextendible
unextensible
unflexible
ungiving
unlimber
unmalleable
unmoved
unpliable
all-enfolding
biocompatible
collagenous
containingan
factor-b
gravity-defying
hyperfine
immiscible
incompressible
low-energy
nontoxic
small-angle
straight-laced
uncharged
unconvinced
unelastic
uninformative
unpliant
unresponsive
unsubmissive
unsusceptible
anaplastic
bombastic
desmoplastic
drastic
dynastic
ecclesiastic
elastic
enthusiastic
fantastic
gymnastic
iconoclastic
interscholastic
monastic
onomastic
sarcastic
scholastic
stochastic
thermoplastic
unenthusiastic