fester

Fester means to stay or remain in an unpleasant or unhealthy state.

Imagine you have a cut that's not healing properly - it might start to fester. This means it's not just being slow to heal, but also getting worse and maybe even becoming infected. We often use the word 'fester' when talking about physical things like cuts or sores, but it can also be used in other situations where something is stuck or remaining in a bad place. For example, if you're feeling anxious or depressed for a long time and don't make any changes to help yourself, that emotional state might start to fester too.