foil (

     n 1: a piece of thin and flexible sheet metal; "the photographic
          film was wrapped in foil"
     2: a device consisting of a flat or curved piece (as a metal
        plate) so that its surface reacts to the water it is
        passing through; "the fins of a fish act as hydrofoils"
        [syn: hydrofoil]
     3: picture consisting of a positive photograph or drawing on a
        transparent base; viewed with a projector [syn: transparency]
     4: a light slender flexible sword tipped by a button
     v 1: enhance by contrast; "In this picture, the figures are
          foiled against the background"
     2: hinder or prevent (the efforts, plans, or desires) of; "What
        ultimately frustrated every challenger was Ruth's amazing
        September surge"; "foil your opponent" [syn: thwart, queer,
         spoil, scotch, cross, frustrate, baffle, bilk]
     3: cover or back with foil; "foil mirrors"