flinty (adj.)
- adamant
- adamantine
- bony
- bowelless
- callous
- calloused
- case-hardened
- cast-iron
- concrete
- constant
- corneous
- cruel
- dense
- dour
- firm
- fixed
- granitelike
- granitic
- grim
- hard
- hard-core
- hardened
- hardhearted
- harsh
- heartless
- horny
- immovable
- immutable
- impervious
- implacable
- inclement
- inelastic
- inexorable
- inflexible
- insensitive
- intransigent
- inured
- iron
- ironlike
- irreconcilable
- lithic
- loyal
- merciless
- obdurate
- osseous
- pachydermatous
- pitiless
- relentless
- remorseless
- resistant
- resistive
- rigid
- rigorous
- rock-ribbed
- rocklike
- rocky
- ruthless
- set
- settled
- slaty
- solid
- staunch
- steadfast
- steady
- steely
- stern
- stiff
- stone
- stonelike
- stony
- thick-skinned
- tough
- true
- unaffected
- unalterable
- unbending
- unchangeable
- uncompassionate
- uncompromising
- unfeeling
- unflappable
- unforgiving
- unmerciful
- unmoved
- unpitying
- unrelenting
- unremorseful
- unshaken
- unswerving
- unsympathetic
- unsympathizing
- unyielding
The tyrant custom, most grave senators,
Hath made the flinty and steel couch of war
My thrice-driven bed of down.
