eldritch (adj.) Look up eldritch at Dictionary.com
"hideous, ghastly, weird," c. 1500, of uncertain origin; apparently somehow from elf (compare Scottish variant elphrish), an explanation OED finds "suitable;" Watkins connects its elements with Old English el- "else, otherwise" (from PIE root *al- (1) "beyond") + rice "realm" (from PIE root *reg- "move in a straight line," with derivatives meaning "to direct in a straight line," thus "to lead, rule").