hard-core

The compound "hard-core" originated in the late 19th century, initially used literally to describe the solid, central rubble found in foundations or roadbeds. The term's logic evolved metaphorically by the early 20th century. "Hard" conveys unyielding firmness and severity, while "core" signifies the essential, central part of something. Thus, the combination came to describe the most intensely committed, unwavering, or extreme faction within a group or ideology, as they form the solid, unshakeable center. This semantic shift from physical solidity to figurative steadfastness allowed the term to later describe extreme styles of music and explicit material, all denoting an uncompromising, intense form.

Structure: hard (firm, severe) + core (center, essence) hard: From Old English 'heard', meaning "solid, firm, severe, difficult." It is a Germanic root. core: From Middle English, possibly from Old French 'cuer' (heart), ultimately from Latin 'cor' (heart), meaning the central or most important part.