Fes"ter (?), v. i. [imp. & p. p. Festered (?); p. pr. & vb. n. Festering.] [OE. festern, fr. fester, n.; or fr. OF. festrir, fr. festre, n. See Fester, n.] 1. To generate pus; to become imflamed and suppurate; as, a sore or a wound festers.

Wounds immedicable
Rankle, and fester, and gangrene.

Unkindness may give a wound that shall bleed and smart, but it is treachery that makes it fester.

Hatred . . . festered in the hearts of the children of the soil.

2. To be inflamed; to grow virulent, or malignant; to grow in intensity; to rankle.

Fes`ter, v. t. To cause to fester or rankle.

For which I burnt in inward, swelt'ring hate,
And festered ranking malice in my breast.

Fes"ter, n. [OF. festre, L. fistula a sort of ulcer. Cf. Fistula.] 1. A small sore which becomes inflamed and discharges corrupt matter; a pustule.

2. A festering or rankling.

The fester of the chain their necks.

• To become septic.
  
• To become rotten.
  
• To worsen, especially due to lack of attention.
       Deal with the problem immediately. Do not let it fester.