In excellent health, in good working order. The proverbial likening of human good health to a fiddle dates from 1600 or earlier, but there is no completely convincing explanation of the analogy. It appeared in print in the early seventeenth century and was in John Ray’s proverb collection of 1678. Fit in those days meant “appropriate,” as “fitting” still does, but why a fiddle should be considered especially appropriate is unknown. It was only in the nineteenth century that the meaning of physical fitness was attached to the expression, where it remains today.