An Etymological Dictionary of the German Language/grell

by Friedrich Kluge

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