having hardness and rigidity but little tensile strength; breaking readily with a comparatively smooth fracture, as glass.

easily damaged or destroyed; fragile; frail

a brittle marriage.

lacking warmth, sensitivity, or compassion; aloof; self-centered

a self-possessed, cool, and rather brittle person.

having a sharp, tense quality

a brittle tone of voice.

unstable or impermanent; evanescent.

a confection of melted sugar, usually with nuts, brittle when cooled

peanut brittle.

to be or become brittle; crumble.