Meaning of foil
Definition of foil
anything that serves by contrast to call attention to another thing's good qualities; "pretty girls like plain friends as foils"
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"
picture consisting of a positive photograph or drawing on a transparent base; viewed with a projector
hinder or prevent (the efforts, plans, or desires) of; "What ultimately frustrated every challenger was Ruth's amazing September surge"; "foil your opponent"