inflexible in WordNet English dictionary

1. resistant to being bent
   "an inflexible iron bar"; "an inflexible knife blade";
   inflexible 
   
2. incapable of change
   "a man of inflexible purpose"
   inflexible 
   
3. not making concessions
   "took an uncompromising stance in the peace talks"; "uncompromising honesty"
   uncompromising  sturdy  inflexible 
   
4. incapable of adapting or changing to meet circumstances
   "a rigid disciplinarian"; "an inflexible law"; "an unbending will to dominate"
   inflexible  rigid  unbending