fester

American  

[fes-ter] / ˈfɛs tər /

verb (used without object)

1. to form pus; generate purulent matter; suppurate.

2. to cause ulceration, as a foreign body in the flesh.

3. to putrefy or rot.

4. to rankle, as a feeling of resentment.

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verb (used with object)

1. to cause to rankle.

   Malice festered his spirit.

noun

1. an ulcer; a rankling sore.

2. a small, purulent, superficial sore.

fester British  

/ ˈfɛstə /

verb

1. to form or cause to form pus

2. (intr) to become rotten; decay

3. to become or cause to become bitter, irritated, etc, esp over a long period of time; rankle

   resentment festered his imagination

4. informal (intr) to be idle or inactive

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noun

1. a small ulcer or sore containing pus

Other Word Forms

• unfestered
  adjective
• unfestering
  adjective

Etymology

Origin of fester

1350–1400; (noun) Middle English festir, festre < Anglo-French, Old French festre < Latin fistula fistula (for -l- > -r- cf. chapter); (v.) Middle English festryn, derivative of the noun or < Old French festrir

Explanation

To fester is to grow and spread, not in a good way. When a cut gets infected it starts to fester and smell bad. Emotional wounds stink too, like when you hold on to anger or pain until it starts to fester and explodes. Fester is a verb describing what happens to a wound or a sore that gets worse and has liquid, or pus, oozing out. Infections cause cuts, broken bones, and diseases to fester. Dead bodies can fester too — as they decompose. Things that fester have a decaying odor, and bad feelings can have a decaying effect on friendships and the heart. Letting bitter emotions fester often leads to their getting worse.

Example Sentences

Sweeping contentious issues under the rug and relegating them to wanton aggravation is one major way of letting these same topics fester.

From Salon • Apr. 3, 2026

And over six seasons, the series examined the under-explored territory that lay between two world wars—a kind of historical trench in which all manner of skullduggery could fester and bloom.

From The Wall Street Journal • Mar. 19, 2026

"I think for everybody there was an element of it was going to happen because antisemitism has been allowed to grow and fester and become normalised," Finlay said.

From BBC • Feb. 13, 2026

"We saw the police stand by and do nothing and, sadly, we've seen that from that moment on hate was allowed to fester."

From Barron's • Dec. 17, 2025

"And your breast must be washed and sewn, lest the wound fester."

From "A Game of Thrones" by George R.R. Martin

Related Words

• smolder