Inflexible, a.
Etymology: [L. inflexiblis: cf. F. inflexible. See In- not, and Flexible.]
1. Not capable of being bent; stiff; rigid; firm; unyielding.
2. Firm in will or purpose; not to be turned, changed, or altered; resolute; determined; unyieding; inexorable; stubborn. "Inflexibleas steel." Miltom. Amanof upright and inflexibletemper . . . can overcome all private fear. Addison.
3. Incapable of change; unalterable; immutable. The nature of things is inflexible. I. Watts.
Syn. -- -- Unbending; unyielding; rigid; inexorable; pertinacious; obstinate; stubborn; unrelenting.
Shades of meaning
Fernald has no entry of its own for inflexible; he lists it under obstinate, severe.
Where he writes about it:
The unyielding conduct which we approve we call decided, firm, inflexible, resolute; that which we condemn we are apt to term headstrong, obstinate, stubborn. — from obstinate
Synonyms
obstinatesevereausterecontumaciousdecideddetermineddoggedfirmfixedhardharshheadstrongheadyimmovableindomitableinexorableintractablemorosemulishobdurateopinionatedpersistentpertinaciousrefractoryrelentlessresoluteresolvedrigidrigoroussternstiffstrictstubbornuncompromisingunconquerableunflinchingunmitigatedunrelentingunyielding