Brash, n. [See Brash brittle.] 1. A rash or eruption; a sudden or transient fit of sickness.
2. Refuse boughs of trees; also, the clippings of hedges. Wright.
3. (Geol.) Broken and angular fragments of rocks underlying alluvial deposits. Lyell.
4. Broken fragments of ice. Kane.
Water brash(Med.), an affection characterized by a spasmodic pain or hot sensation in the stomach with a rising of watery liquid into the mouth; pyrosis. — Weaning brash(Med.), a severe form of diarrhea which sometimes attacks children just weaned.