foil
Cross references: 1. frustrate 1. foil \'fo.i(*)l\ vt [ME foilen to trample, full cloth, fr. MF fouler - more at FUL]L obs 1: TRAMPLE 2a: to prevent from attaining an end : DEFEAT 2b: to bring to naught 2. foil n archaic 1: DEFEAT archaic 2: the track or trail of an animal 3a: a fencing weapon with a flat guard and a light flexible blade tapering to a blunt point pl 3b: the art or practice of fencing with foils 3. foil n [ME, fr. MF foille (fr. L folia, pl. of folium) & foil,] fr. L folium - more at BLADE 1: a plant leaf - used in compounds 2a: an indentation between cusps in Gothic tracery 2b: one of several arcs that enclose a complex figure 3a: very thin sheet metal 3b: a thin coat of tin or silver laid on the back of a mirror 4: a thin piece of metal or other material put under a paste or inferior st one to add color or brilliancy 5: one that serves as a contrast to another 4. foil vt 1: to back or cover with foil 2: to enhance by contrast
Webster's English Dictionary