Origin: 1275–1325; ME (
h)
orrible < OF < L
horribilis, equiv. to
horr- (s. of
horrēre to stand on end, bristle with fear) +
-ibilis -ible 
Related forms: hor⋅ri⋅ble⋅ness, noun
hor⋅ri⋅bly, adverb
Synonyms:
1. terrible, awful, appalling, frightful; hideous, grim, ghastly, shocking, revolting, repulsive, horrid, horrendous, horrifying, repellent.
Antonyms:
1. attractive.