Ague - (Webster's 1828 Dictionary)
A'GUE, n. a'gu,
1. The cold fit which precedes a fever, or a paroxysm of fever in intermittents. It is accompanied with shivering.
2. Chilliness; a chill, or state of shaking with cold, though in health.
3. It is used for a periodical fever, an intermittent, whether quotidian, tertian, or quartan. In this case, the word, which signifies the preceding cold fit, is used for the disease.
A'GUE, v.t. To cause a shivering in; to strike with a cold fit.