A stiff or coarse hair.

“the bristles of a pig”

The hairs or other filaments that make up a brush, broom, or similar item.

To rise or stand erect, like bristles.

Abound, to have an abundance of something

(with at) To be on one's guard or raise one's defenses; to react with fear, suspicion, or distance.

“The employees bristled at the prospect of working through the holidays.”