fester

UK: /ˈfɛstə^r/ US: /ˈfɛstɚ/ ,(fes′tər)

WordReference Random House Learner's Dictionary of American English © 2026

fes•ter /ˈfɛstɚ/   v. [no object]

1. Physiology to form pus;
   putrefy:
   a festering wound.
2. (of hatred, anger, jealousy, etc.) to grow stronger or worse gradually:
   The desire for revenge festered in her heart.

WordReference Random House Unabridged Dictionary of American English © 2026

fes•ter  (fes′tər), v.i. 

1. Physiology to form pus;
   generate purulent matter;
   suppurate.
2. Physiology to cause ulceration, as a foreign body in the flesh.
3. Physiology to putrefy or rot.
4. to rankle, as a feeling of resentment.

v.t. 

5. to cause to rankle:
   Malice festered his spirit.

n. 

6. Physiology an ulcer;
   a rankling sore.
7. Physiology a small, purulent, superficial sore.

• Old French festrir
• Latin fistula fistula (for -l- -r- compare chapter); (verb, verbal) Middle English festryn, derivative of the noun, nominal or
• Anglo-French, Old French festre
• (noun, nominal) Middle English festir, festre 1350–1400

Collins Concise English Dictionary © HarperCollins Publishers::

fester / ˈfɛstə/ verb

1. to form or cause to form pus
2. (intransitive) to become rotten; decay
3. to become or cause to become bitter, irritated, etc, esp over a long period of time; rankle

noun

1. a small ulcer or sore containing pus

Etymology: 13th Century: from Old French festre suppurating sore, from Latin: fistula