adamantine
1. [ adjective ] having the hardness of a diamond
Related terms: hard
2. [ adjective ] consisting of or having the hardness of adamant
Related terms: diamond
3. [ adjective ] not capable of being swayed or diverted from a course; unsusceptible to persuasion
Synonyms: adamant inexorable intransigent
Examples:

"he is adamant in his refusal to change his mind" "Cynthia was inexorable she would have none of him"- W.Churchil

Related terms: inflexible
Similar spelling:   adamant
  adamance
  adamantly
  admonition
  admonisher
  admonished
  administer
  adynamia
  admonish
  admonishment
  admonitory