1. An acute fever: An ague, such as malaria, is marked by paroxysms of chills, fever, and sweating, and recurring at regular intervals.
2. A fit of shivering, a chill: Ague can refer to coldness, shuddering, and fever.
3. Etymology: aigue entered English usage in the 14th century, having crossed the English channel from the Middle French aguë.

The word shares the same origin as acute. It comes from the Latin acutus, "sharp or pointed". A fievre aigue in French was a sharp, pointed, or acute fever.

1. An acute febrile state with chills: Shaking ague can be a fit of fever accompainied by shivering and by pains in the joints and bones.
2. In medicine, an obsolete term for the severe form of malarial paroxysm: Shaking ague can be a violent attack of sickness which may be due to the sudden occurrence of symptoms, or the acute exacerbation, or the abrupt worsening, of preexisting symptoms.