horripilation n.

early 14c., "feeling of disgust;" late 14c., "emotion of horror or dread," also "thing which excites horror," from Old French horror (12c., Modern French horreur) and directly from Latin horror "dread, veneration, religious awe," a figurative use, literally "a shaking, trembling (as with cold or fear), shudder, chill," from horrere "to bristle with fear, shudder," from PIE root *ghers- "to bristle" (source also of Sanskrit harsate "bristles," Avestan zarshayamna- "ruffling one's feathers," Latin eris (genitive) "hedgehog," Welsh garw "rough").

Also formerly in English "a shivering," especially as a symptom of disease or in reaction to a sour or bitter taste (1530s); "erection of the hairs on the skin" (1650s); "a ruffling as of water surface" (1630s). As a genre in film, 1934. Chamber of horrors originally (1849) was a gallery of notorious criminals in Madame Tussaud's wax exhibition. Other noun forms are horribility (14c., now rare or disused), horribleness (late 14c.), horridity (1620s), horridness (1610s).

mid-14c., "downy plumage;" late 15c, "fine, soft hair," from Anglo-French pyle or Middle Dutch pijl, both from Latin pilus "a hair" (source of Italian pelo, Old French pel), a word of uncertain origin. Phonological evidence rules out transmission of the English word via Old French cognate peil, poil. Meaning "soft, raised surface of a regular and closely set kind upon cloth" is from 1560s.