Etymology tree Proto-Indo-European *ǵʰers-der. Proto-Indo-European *ǵʰr̥s-éh₁-(ye)-ti Proto-Italic *horzēō Latin horreō Proto-Indo-European *dʰeh₁-der. Proto-Italic *-iðos Latin -idus Latin horridusbor. English horrid Borrowed from Latin horridus (“rough, bristly, savage, shaggy, rude”), from horrere (“to bristle”). See horrent, horror, ordure.