(1):

(n.) A small sore which becomes inflamed and discharges corrupt matter; a pustule.

(2):

(n.) To generate pus; to become imflamed and suppurate; as, a sore or a wound festers.

(3):

(n.) To be inflamed; to grow virulent, or malignant; to grow in intensity; to rankle.

(4):

(n.) A festering or rankling.

(5):

(v. t.) To cause to fester or rankle.