As a verb fester
is to become septic; to become rotten.
As a noun mester is
To become septic; to become rotten.
To worsen, especially due to lack of attention.
- Wounds immedicable / Rankle, and fester , and gangrene.
- Deal with the problem immediately; do not let it fester .
To cause to fester or rankle.
- Hatred festered in the hearts of the children of the soil.
- For which I burnt in inward, swelt'ring hate, / And fester'd rankling malice in my breast.