[EDITOR'S NOTE] I could not find horripilative in an on-line dictionary, but you’ll get the gist of his meaning by reading the definitions below. In the future, and because of DFW’s way with words, I’ll probably avoid adding these notes and leave all inferences up to you, the dear reader.
Definition
[1. horripilate] (verb) cause (someone’s) hair to stand on end and to have goosebumps. [2. horripilation] (noun) a real or fancied bristling of the hair of the head or body, resulting from disease, terror, chilliness, etc.
DFW's Sentence This was Johnson's first fiction after the horripilative lyric poetry of "Incognito Lounge."
My Sentence Since she considered herself something of an expert on the topic, listening to the kids at the Food Mall compare Jonah Hill to Marlon Brando was a horripilative cinemaphilic travesty she couldn't shake for days.
01: DFW Source: Overlooked: Five direly underappreciated U.S. novels >1960
02: Definition Source: Ninjawords (verb) and Ninjawords (noun)