Akademik

adamant
adj. & n.
—adj. stubbornly resolute; resistant to persuasion.
—n. archaic diamond or other hard substance.
Derivatives:
adamance n. adamantine adj. adamantly adv.
Etymology: OF adamaunt f. L adamas adamant- untameable f. Gk (as A-(1), damao to tame)

Useful english dictionary. 2012.