FLINT n.
Anything extremely hard, unimpressible, and unyielding, like flint. "A heart of flint." Spenser. Flint age. (Geol.) Same as Stone age, under Stone. -- Flint brick, a fire made principially of powdered silex. -- Flint glass. See in the Vocabulary. -- Flint implements (Archæol.), tools, etc., employed by men before th…
IMPENETRABLE a.
Inaccessible, as to knowledge, reason, sympathy, etc.; unimpressible; not to be moved by arguments or motives; as, an impenetrable mind, or heart. They will be credulous in all affairs of life, but impenetrable by a sermon of the gospel. Jer. Taylor.