To frustrate; to defeat; to render vain or nugatory, as an effort or attempt. The enemy attempted to pass the river, but was foiled. He foiled his adversaries. And by a mortal man at length am foiled.

To blunt; to dull. When light wing’d toys of feathered cupid foil - .

To defeat; to interrupt, or to render imperceptible; as, to foil the scent in a chase.

Defeat; frustration; the failure of success when on the point of being secured; miscarriage. Death never won a stake with greater toil, nor e’er was fate to near a foil.

A blunt sword, or one that has a button at the end covered with leather; used in fencing. Isocrates contended with a foil, against Demosthenes with a sword.

A leaf or thin plate of metal used in gilding.

Among jewelers, a thin leaf of metal placed under precious stones, to make them appear transparent, and to give them a particular color, as the stone appears to be of the color of the foil. Hence,

Any thing of another color, or of different qualities, which serves to adorn, or set off another thing to advantage. Hector has a foil to set him off.

A thin coat of tin, with quicksilver, laid on the back of a locking glass, to cause reflection.