An Etymological Dictionary of the German Language/Annotated/grell

by Friedrich Kluge

grell, adjective, ‘shrill, glaring, dazzling,’ from Middle High German grël(ll), ‘rough, angry,’ allied to Middle High German grëllen, ‘to cry aloud, angrily’; wanting in Old High German; compare'AS. griellan, ‘to gnash, sound harshly.’ The root and further cognates are unknown; akin to Grille?.