adj. 25B6; adjective
glass is a brittle material : BREAKABLE, fragile, delicate; splintery; formal frangible.
a brittle laugh : HARSH, hard, sharp, grating.
a brittle young woman : EDGY, nervy, anxious, unstable, highly strung, tense, excitable, skittish, neurotic; informal uptight, jumpy.
flexible, resilient, soft, relaxed.