Entry 6 senses · 3 variants Webster, 1913 Brash /(brăsh)/ · IPA /bɹæʃ/ a. a. n. 01 a. Hasty in temper; impetuous. 1. Hasty in temper; impetuous. 02 a. Brittle, as wood or vegetables. 1. Brittle, as wood or vegetables.[Colloq., U. S.] 03 n. A rash or eruption; a sudden or transient fit of sickness. 1. A rash or eruption; a sudden or transient fit of sickness. 2. Refuse boughs of trees; also, the clippings of hedges.[Prov. Eng.] 3. Broken and angular fragments of rocks underlying alluvial deposits.(Geol.) 4. Broken fragments of ice. Phrases & compounds Water brash — 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 — a severe form of diarrhea which sometimes attacks children just weaned.