flinty

the word "flinty" is a straightforward english formation from the old english noun "flint," which refers to the extremely hard, sedimentary form of quartz. the "-y" suffix, also of old english origin, is a productive adjectival ending used to denote possession of a quality. the semantic evolution is direct: the primary characteristic of flint is its hardness, which was metaphorically extended to describe people or expressions that are similarly hard, unyielding, and devoid of softness or emotion. thus, the modern abstract meaning of sternness or harshness is a logical figurative transfer from the literal property of the stone.

Structure: flint (hard stone) + y (adjective-forming suffix) flint (old english, a hard grey rock used in tools and weapons) + y (old english, suffix forming adjectives meaning "characterized by; full of; having the quality of").