To become worse or more intense, especially through long-term neglect or indifference. The unresolved conflict continued to fester, leading to more tension in the office.
To generate pus; to form a pus-filled sore. The wound began to fester after it was left untreated for several days.
To cause increasing irritation or bitterness. His resentment towards his colleague festered over time, affecting their working relationship.
To undergo decay or putrefaction; to rot. If the fruit is left in the heat, it will quickly fester and attract flies.