to tread under foot; to trample.-to render (an effort or attempt) vain or nugatory; to baffle; to outwit; to balk; to frustrate; to defeat.-to blunt; to dull; to spoil; as, to foil the scent in chase.-to defile; to soil.-failure of success when on the point of attainment; defeat; frustration; miscarriage.-a blunt weapon used in fencing, resembling a smallsword in the main, but usually lighter and having a button at the point.-the track or trail of an animal.-a leaf or very thin sheet of metal; as, brass foil; tin foil; gold foil.-a thin leaf of sheet copper silvered and burnished, and afterwards coated with transparent colors mixed with isinglass; -- employed by jewelers to give color or brilliancy to pastes and inferior stones.-anything that serves by contrast of color or quality to adorn or set off another thing to advantage.-a thin coat of tin, with quicksilver, laid on the back of a looking-glass, to cause reflection.-the space between the cusps in gothic architecture; a rounded or leaflike ornament, in windows, niches, etc. a group of foils is called trefoil, quatrefoil, quinquefoil, etc., according to the number of arcs of which it is composed.