An Etymological Dictionary of the German Language/Annotated/Brunst

by Friedrich Kluge

Brunst, feminine, from the equivalent Middle High German brunst, feminine, ‘burning, fire, glow, heat, devastation by fire’ (Brunftzeit, see Brunft); Old High German brunst, Gothic brunsts. In English this derivative from the root of brennen is wanting (compare Kunst from kennen); the s before the suffix t is due to the double n of the verb.