adamantine Synonyms

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