A fever, especially one characterized by fits of shivering and sweating, historically associated with malaria or similar illnesses.
From Old French 'ague' from Latin 'acuta' (sharp or acute fever), eventually adopted into Middle English to describe fever-related illnesses common in damp, marshy areas.
Before we understood malaria was caused by mosquitoes, people simply called the shaking and fever 'ague'—Elizabethan England was plagued by it, and Shakespeare's characters often reference it, making it a window into how disease shaped daily medieval and Renaissance life.
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