The most common and most likely answer to this crossword clue is the 8 letter word BRISTLES
I've seen this crossword clue in Independent
B
R
I
S
T
L
E
S
More clues leading to the result BRISTLES
Buddy explains!
The straight part
We know that "hairs" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case hairs = bristles.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does BRISTLES mean?
BRISTLES noun- A stiff or coarse hair.
- 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.
- To fix a bristle to.