impervious to pleas, persuasion, requests, reason;
Determined
very hard native crystalline carbon valued as a gem
GRANITE
something having the quality of granite (unyielding firmness); "a man of granite"
plutonic igneous rock having visibly crystalline texture; generally composed of feldspar and mica and quartz
HARD
causing great damage or hardship; "industries hit hard by the depression"; "she was severely affected by the bank's failure"
with firmness; "held hard to the railing"
earnestly or intently; "thought hard about it"; "stared hard at the accused"
with pain or distress or bitterness; "he took the rejection very hard"
not easy; requiring great physical or mental effort to accomplish or comprehend or endure; "a difficult task"; "nesting places on the cliffs are difficult of access"; "difficult times"; "why is it so hard for you to keep a secret?"
very near or close in space or time; "it stands hard by the railroad tracks"; "they were hard on his heels"; "a strike followed hard upon the plant's opening"
characterized by effort to the point of exhaustion; especially physical effort; "worked their arduous way up the mining valley"; "a grueling campaign"; "hard labor"; "heavy work"; "heavy going"; "spent many laborious hours on the proj
HARDLINE
firm and uncompromising; "a hard-line policy"
IRON
extremely robust; "an iron constitution"
implement used to brand live stock
a heavy ductile magnetic metallic element; is silver-white in pure form but readily rusts; used in construction and tools and armament; plays a role in the transport of oxygen by the blood
home appliance consisting of a flat metal base that is heated and used to smooth cloth
press and smooth with a heated iron; "press your shirts"; "she stood there ironing"
a golf club that has a relatively narrow metal head
OBDURATE
showing unfeeling resistance to tender feelings; "his flinty gaze"; "the child's misery would move even the most obdurate heart"
stubbornly persistent in wrongdoing
RIGID
incapable of or resistant to bending;
designating an airship or dirigible having a form maintained by a stiff unyielding frame or structure
incapable of adapting or changing to meet circumstances;
fixed and unmoving; "with eyes set in a fixed glassy stare";
incapable of compromise or flexibility
Stiff
STEELY
resembling steel in hardness
resembling steel as in hardness; "steely eyes"; "steely nerves like those of a steeplejack"
STERILE
deficient in originality or creativity; lacking powers of invention; "a sterile ideology lacking in originality"; "unimaginative development of a musical theme"; "uninspired writing"
incapable of reproducing; "an infertile couple"
free of or using methods to keep free of pathological microorganisms; "a sterile operating area"; "aseptic surgical instruments"; "aseptic surgical techniques"
STRICT
severe and unremitting in making demands; "an exacting instructor"; "a stern disciplinarian"; "strict standards"
rigidly accurate; allowing no deviation from a standard; "rigorous application of the law"; "a strict vegetarian"
characterized by strictness, severity, or restraint