Grisly
Old English grislic ‘terrifying’, of Germanic origin; related to Dutch griezelig .
wiktionary
From Middle English grisely, grysly, grissliȝ, griselich, grislich, from Old English grisliċ(“grisly, horrible; dreadful, horrid”), from grīsan(“to shudder with horror; to tremble, to be terrified; to make tremble, to terrify; to agrise, grise”) (unattested but implied in āgrīsan) [1] + -lic(suffix forming adjectives meaning ‘characteristic of, pertaining to’).
The word may also be an aphetic form of Old English ongrislic, agrisenliċ, the past participle of agrīsan(“to agrise”). [2]
Compare Danish grusom, Swedish gräslig, Middle Dutch grezelijc (modern Dutch griezelig), Middle High German grisenlich (modern German grässlich, grausen).
From grisle(“ horror, terror”) + -ly; compare Middle Dutch griselike, Middle Low German grislike.
etymonline
grisly (adj.)
Old English grislic (in compounds) "horrible, dreadful," from root of grisan "to shudder, fear," a general Germanic word (cognates: Old Frisian grislik "horrible," Middle Dutch grisen "to shudder," Dutch griezelen, German grausen "to shudder, fear," Old High German grisenlik "horrible;" of unknown origin; Watkins connects it with the PIE root *ghrei- "to rub," on notion of "to grate on the mind." See also gruesome, to which it probably is connected in some way. Related: Grisliness.
