What term is used for a condition that comes on suddenly?

The term "acute" refers to a condition that develops suddenly and is often severe in nature. Acute conditions typically manifest with rapid onset and can involve intense symptoms. They are often distinct from chronic conditions, which develop gradually over time and last for an extended period. Acute conditions can result from various causes, including infections, injuries, or other medical events that require immediate attention.

In contrast, chronic conditions are characterized by symptoms that persist over a long time, while subacute conditions may linger longer than acute but not as long as chronic conditions. Intermittent refers to conditions that come and go, rather than having a sudden onset. Thus, acute is the most appropriate term for describing a condition that begins suddenly and can often signify a critical situation that needs prompt medical intervention.