"Bristliest" is a word used to describe the extremity of prickliness or roughness on a surface. Synonyms for this word include "spikiest," "prickliest," "thorniest," "barbed," and "harshest." These words all connote a sense of discomfort or danger to the touch, and are often used to describe things like cacti, thistles, or unruly hair. Other possible synonyms for "bristliest" may include "stiffest," "coarsest," "raspiest," or "roughest." Whatever synonym one may choose to use, it is clear that this word describes an object or sensation that is not pleasant to experience.