Synonyms of the word

inflexible

• adj. Not flexible; not capable of bending or being bent; stiff; rigid; firm; unyielding.
• adj. Not willing to change, e.g. one's opinion or habits; obstinate; stubborn; resolute; determined.

adamant

• adj. Firm; unshakeable; unyielding; determined.
• adj. (of an object) Similar to the adamant; very difficult to break, pierce, or cut.
• n. An imaginary rock or mineral of impenetrable hardness; a name given to the diamond and other substances…
• n. An embodiment of impregnable hardness.
• n. A magnet; a lodestone.

adamantine

• adj. Made of adamant, or having the qualities of adamant; incapable of being broken, dissolved, or penetrated.
• adj. Like the diamond in hardness or luster.

brassbound

• adj. Bound with brass.

die-hard

• adj. Alternative spelling of diehard.
• n. Alternative spelling of diehard.

fossilised

• adj. Non-Oxford British English standard spelling of fossilized.

fossilized

• v. simple past tense and past participle of fossilize.
• adj. In a state of fossilization; preserved in rock.

hard-core

• adj. Alternative form of hardcore.

hard-line

• adj. Alternative spelling of hardline.

hardline

• n. (business) A retail product collection consisting primarily of hardware targeting the do-it-yourself customer.
• n. (business) A retail product collection which includes many non-information goods, such as home appliances,…
• n. (telephony) A physical wire or cable connection; landline.
• adj. uncompromising; rigidly holding to a set of beliefs.
• adj. (business) belonging to a hardline.

inelastic

• adj. lacking elasticity; inflexible, unyielding.

inexorable

• adj. Unable to be persuaded; relentless; unrelenting.
• adj. Impossible to stop or prevent; inevitable.
• adj. Adamant; severe.

intransigent

• adj. Unwilling to compromise or moderate a position; unreasonable; irreconcilable; stubborn.
• n. A person who is intransigent.

ironclad

• adj. Covered with iron, steel, or some metal, armor-plated.
• adj. (figuratively) Solid or certain; not able to be disputed or questioned; irrefutable.
• adj. (figuratively) Rigorous; severe; exacting.
• n. A metal-plated ship, vessel, or vehicle.
• n. (military) An armor-plated warship.

muscle-bound

• adj. Alternative form of musclebound.

ossified

• adj. Having undergone the process of ossification (transformation into bone).
• adj. (of ideas or attitudes) Inflexible, old-fashioned.
• v. simple past tense and past participle of ossify.

rigid

• adj. Stiff, rather than flexible.
• adj. Fixed, rather than moving.
• adj. Rigorous and unbending.
• adj. Uncompromising.
• n. A bicycle with no suspension system.

rock-ribbed

• adj. having rocky cliffs or outcroppings.
• adj. obstinately firm and unyielding in one's opinions.

semirigid

• adj. Partially rigid.

stiff

• adj. (of an object) Rigid, hard to bend, inflexible.
• adj. (figuratively, of policies and rules and their application and enforcement) Inflexible; rigid.
• adj. (of a person) Formal in behavior; unrelaxed.
• adj. (colloquial) Harsh, severe.
• adj. (of muscles or parts of the body) Painful as a result of excessive or unaccustomed exercise.
• adj. Potent.
• adj. Dead, deceased.
• adj. (of a penis) Erect.
• adj. (cooking, of whipping cream or egg whites) Beaten until so aerated that they stand up straight on their…
• adj. (mathematics) Of an equation: for which certain numerical solving methods are numerically unstable, unless…
• n. An average person, usually male, of no particular distinction, skill, or education, often a working stiff…
• n. A person who is deceived, as a mark or pigeon in a swindle.
• n. (slang) A cadaver, a dead person.
• n. (US) A person who leaves (especially a restaurant) without paying the bill.
• n. (blackjack) Any hard hand where it is possible to exceed 21 by drawing an additional card.
• v. To fail to pay that which one owes (implicitly or explicitly) to another, especially by departing hastily.
• v. to cheat someone.
• v. to tip ungenerously.

sturdy

• adj. Of firm build; stiff; stout; strong.
• adj. Solid in structure or person.
• adj. (obsolete) Foolishly obstinate or resolute; stubborn.
• adj. Resolute, in a good sense; or firm, unyielding quality.
• n. A disease in sheep and cattle, marked by great nervousness, or by dullness and stupor.

unadaptable

• adj. Not adaptable.

unbending

• adj. inflexible and not yielding.
• adj. very reserved, aloof and antisocial.
• v. present participle of unbend.
• n. The act of one who unbends.

uncompromising

• adj. Inflexible and unwilling to negotiate or make concessions.
• adj. Principled.