adamantine Synonyms

adamant inexorable intransigent strong stony stone stiff stern steely solid set stubborn tough unbending uncompliant unbendable self-opinionated unforgiving hardheaded unbreakable brassbound unyielding unrelenting uncompromising rocky rigid resolute immovable hard-handed hardened hard grim flinty fixed firm dogged impenetrable implacable relentless pat ossified obstinate obdurate iron inflexible indestructible incompliant determined