foil

(noun) a piece of thin and flexible sheet metal. Examples: "The photographic film was wrapped in foil."

(noun) anything that serves by contrast to call attention to another thing's good qualities. Synonyms: enhancer. Examples: "Pretty girls like plain friends as foils."

(noun) 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. Synonyms: hydrofoil. Examples: "The fins of a fish act as hydrofoils."

(noun) picture consisting of a positive photograph or drawing on a transparent base; viewed with a projector. Synonyms: transparency.

(noun) a light slender flexible sword tipped by a button.

(verb) enhance by contrast. Examples: "In this picture, the figures are foiled against the background."

(verb) hinder or prevent (the efforts, plans, or desires) of. Synonyms: thwart, queer, spoil, scotch, cross, frustrate, baffle, bilk. Examples: "What ultimately frustrated every challenger was ruth's amazing september surge." "Foil your opponent."

(verb) cover or back with foil. Examples: "Foil mirrors."