The verb 'fester' means to become worse or more intense, often due to neglect, and can refer to both physical wounds and metaphorical problems. An example would be an untreated wound that becomes infected, while 'heal' is a non-example as it signifies recovery.
The word fester is a verb that means to become worse or more intense, especially through long-term neglect or indifference. In the context of an injury or wound, to fester is to become septic or infected, often producing pus. It can also be used metaphorically to describe a negative feeling or problem that becomes worse over time because it is not dealt with.
An example of the verb 'fester' in a sentence could be: 'The cut on his leg was left untreated, and it began to fester and became painful.' A non-example would be the word 'heal,' as it signifies improvement or recovery, which is the opposite of festering.