grum

From Middle English grom, from Old English grom, gram (“angry, wrathful”), from Proto-Germanic *gramaz (“angry, bearing a grudge”), from Proto-Indo-European *gʰrem- (“to thunder, rub, tear, scratch”). Probably influenced in form by glum. Compare also Danish grum (“cruel, atrocious, fell”), Swedish grym (“cruel, furious, terrible”). See also grim, gram, grump.