WordWeb Online

1. Incapable of change
   "a man of inflexible purpose"
    
2. Not making concessions
   "took an inflexible stance in the peace talks";
   - uncompromising, sturdy
    
3. Resistant to being bent
   "an inflexible iron bar"; "an inflexible knife blade"
    
4. Incapable of adapting or changing to meet circumstances
   "an inflexible law";
   - rigid, unbending

See also: adamant, adamantine, brassbound, die-hard, fossilised [Brit], fossilized, hard-core, hardline, hard-line, inelastic, inexorable, intransigent, ironclad, muscle-bound, ossified, rigid, rock-ribbed [N. Amer], semirigid, stiff, unadaptable

Antonym: flexible

Encyclopedia: Inflexible