1 C1 neutral
(Of hair, fur, or feathers) to stand up stiffly, usually due to fear, cold, or excitement.
"The dog's fur bristled up when it heard the noise outside."
inseparable
bristle up
C1 informal inseparable intransitive
To react with obvious anger, irritation, or defensiveness, often shown in body language; or (of hair or fur) to stand up stiffly.
In plain English
To suddenly get angry or defensive, like how a cat's fur stands up when it's scared or angry.
What does "bristle up" mean?
2 meanings, ordered from most common to least. Color-coded by CEFR level.
2 C1 idiomatic informal
To react with visible irritation, indignation, or defensive anger.
"He bristled up immediately when his motives were questioned."
inseparable
Literal vs figurative
Words literally mean
The literal image is of an animal's bristles or hairs standing upright as a threat display — extended to describe human anger or defensiveness.
Actually means
To suddenly get angry or defensive, like how a cat's fur stands up when it's scared or angry.
Usage tip
Often describes both the physical reaction of an animal (fur standing up) and the figurative human emotional reaction of defensive anger. The figurative sense is more common in literature than in everyday speech.
Words that pair with "bristle up"
Natural word combinations native speakers use most often.
indignation anger fur hairs defensiveness pride
How to conjugate "bristle up"
The five tense forms you'll use most often.
Base
bristle up
I/you/we/they
3rd person
bristles up
he/she/it
Past simple
bristled up
yesterday
Past participle
bristled up
have + pp
-ing form
bristling up
continuous
Hear "bristle up" in the wild
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