Definition

1. Noun:

   • A light, slender sword used in fencing: A flexible sword with a button on the tip, used for thrusting in the sport of fencing.
   • A thin, flexible sheet of metal: A very thin, pliable sheet of metal, often used for wrapping or covering.
   • A person or thing that contrasts with and so emphasizes the qualities of another: Something or someone that, by being different, makes the good qualities of another more noticeable.
   • A hydrofoil: A flat or curved surface on a boat or aircraft that provides lift when moving through water or air.
   • A transparent sheet with an image: A positive photograph or drawing on a transparent base, used for projection.

2. Verb:

   • To prevent the success of something; to thwart: To stop someone's plans or efforts from being successful.
   • To cover or back with foil: To apply a thin sheet of metal to something.
   • To enhance by contrast: To set something off or make it more distinct by placing it against a contrasting background.

Examples of Usage

• Noun:

  • The fencer practiced her parry and thrust with a foil.
  • Wrap the leftover food in aluminum foil before putting it in the refrigerator.
  • His cheerful personality was the perfect foil to her more serious nature.
  • The boat's foils lifted it above the water, allowing for greater speed.

• Verb:

  • The security guard foiled the attempted robbery.
  • The mirrors were foiled to make them more reflective.
  • The dark trees foiled the bright colors of the flowers.

Advanced Usage

• "to act as a foil to": To serve as a contrasting element that highlights something else.
  • The simple vase acts as a foil to the intricate beauty of the flower.

Variants and Related Words

• Hydrofoil (n): A boat equipped with foils that lift the hull out of the water at speed.
• Tin foil (n): A thin sheet made of tin or aluminum, used for wrapping food. (Note: Modern "tin foil" is almost always aluminum.)
• Gold foil (n): A very thin sheet of gold, used in decoration, art, or dentistry.

Synonyms

• Noun (contrast): Contrast, antithesis, counterpoint.
• Verb (thwart): Thwart, frustrate, hinder, prevent, stop.

Related Phrasal Verbs

(This word does not commonly form phrasal verbs.)

Related Idioms

• "run the foil": (Archaic) To retrace one's steps or follow a previous path. This usage is now very rare.
• "serve as a foil": To be used as a contrasting element.
  • The plain background serves as a foil, making the central subject stand out.

Noun

1. a light slender flexible sword tipped by a button
2. picture consisting of a positive photograph or drawing on a transparent base; viewed with a projector
3. 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
4. anything that serves by contrast to call attention to another thing's good qualities
   • pretty girls like plain friends as foils
5. a piece of thin and flexible sheet metal
   • the photographic film was wrapped in foil

Verb

1. cover or back with foil
   • foil mirrors
2. hinder or prevent (the efforts, plans, or desires) of
   • What ultimately frustrated every challenger was Ruth's amazing September surge
   • foil your opponent
3. enhance by contrast
   • In this picture, the figures are foiled against the background