(1) Common sense, (2) imagination, (3) fantasy, (4) estimation, and (5) memory. Common sense is the outcome of the five senses; imagination is the “wit” of the mind; fantasy is imagination united with judgment; estimation estimates the absolute, such as time, space, locality, and so on; and memory is the “wit” of recalling past events.
“Four of his five wits went halting off.”
These are the five witts removyng inwardly: First, `Common witte,' and then `Ymagination,' `Fantasy,' and `Estimation' truely. And `Memory.'
Stephen Hawes: The Passe-tyme of Plesure (1515).
Notwithstanding this quotation, probably the Five Wits mean the wits of the five senses.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894