FOIL (3)

Foil, n. 1. 1. Failure of success when on the point of attainment; defeat; frustration; miscarriage. Milton.
Nor e'er was fate so near a foil. Dryden. 2. 2. A blunt weapon used in fencing, resembling a smallsword in the main, but usually lighter and having a button at the point.
Blunt as the fencer's foils, which hit, but hurt not. Shak. Isocrates contended with a foil against Demosthenes with a word. Mitford. 3. 3. The track or trail of an animal.
To run a foil,to lead astray; to puzzle; — alluding to the habits of some animals of running back over the same track to mislead their pursuers. Brewer.