unyielding (adj.)
- adamant
- adamantine
- bowelless
- bulky
- bullheaded
- cast-iron
- certain
- complaining
- constant
- cruel
- dense
- disputatious
- dissentient
- dissenting
- dour
- durable
- enduring
- fated
- fateful
- firm
- fixed
- flinty
- fractious
- frozen
- fundamentalist
- grim
- hard
- hard-core
- hard-line
- harsh
- headstrong
- heartless
- heavy
- hidebound
- immobile
- immotile
- immovable
- immutable
- impenetrable
- impervious
- implacable
- impregnable
- inclement
- incontestable
- indefeasible
- indomitable
- inelastic
- ineluctable
- inescapable
- inevitable
- inexorable
- inexpugnable
- inextensible
- inflexible
- insuperable
- intractable
- intransigent
- invincible
- inviolable
- invulnerable
- iron
- ironclad
- irreconcilable
- irremovable
- irresistible
- irrevocable
- lasting
- loyal
- massive
- merciless
- mortal
- mulish
- muscle-bound
- necessary
- obdurate
- obstinate
- obstructive
- orthodox
- overpowering
- overwhelming
- pat
- pertinacious
- pigheaded
- pitiless
- procrustean
- puritanic
- rebellious
- recalcitrant
- refractory
- relentless
- reluctant
- remorseless
- repellent
- resistant
- resisting
- resistive
- resistless
- retardant
- rigid
- rigorous
- rock-ribbed
- rockbound
- rugged
- ruthless
- self-willed
- set
- settled
- single-minded
- solid
- sound
- stable
- standpat
- stationary
- staunch
- steadfast
- steady
- steely
- stern
- stiff
- stout
- straightlaced
- straitlaced
- strong
- stubborn
- sturdy
- sure
- tough
- true
- unaffected
- unalterable
- unappeasable
- unassailable
- unavoidable
- unbeatable
- unbending
- unchangeable
- uncompassionate
- uncompromising
- unconquerable
- uncontrollable
- uncooperative
- unfeeling
- unflappable
- unflinching
- unforgiving
- unimpressionable
- unmalleable
- unmerciful
- unmovable
- unmoved
- unmoving
- unpersuadable
- unpitying
- unpreventable
- unreceptive
- unrelenting
- unremorseful
- unresponsive
- unshaken
- unstoppable
- unsubduable
- unsubmissive
- unsurmountable
- unsusceptible
- unswerving
- unsympathetic
- unsympathizing
- well-founded
- well-grounded
- well-made
