the.com/bristles
Short stiff hairs that double as a verb for offended dignity.
means Bristles are stiff, coarse hairs on animals or brushes, or, as a verb, the act of stiffening with sudden indignation.
from From Old English 'byrst,' meaning a stiff hair, kin to the German 'Borste' — the same root that gives us the boar's defensive uprising.
Toothbrush pastMade from boar hair until nylon arrived in 1938.
Body languageHackles rising literally lifts an animal's bristles in threat.
Verbal pivotTo bristle is to mirror an angry hedgehog's posture.