adjective, flint·i·er, flint·i·est.
- composed of, containing, or resembling flint, especially in hardness.
- unyielding; unmerciful; obdurate: a flinty heart.
adjective flintier or flintiest
- of, relating to, or resembling flint
- hard or cruel; obdurate; unyielding
“hard-hearted,” 1530s, from flint + -y (2). Literal sense of “resembling flint” is from 1640s. Related: Flintily; flintiness.