The word 固执 is formed by combining two characters whose core ideas conceptually merge to create a new, unified meaning. The first character, 固, carries the sense of something being solid, hard, or unchangeable, like a fortress. The second, 执, fundamentally means to grasp, hold, or cling to something persistently. When fused, they paint a vivid picture of a mind that is rigidly holding onto its own views, mentally "clinging with a hardened grip". It’s less about grammar and more about this powerful, almost physical metaphor of an inflexible, tenacious adherence to one's own position.