(mathematics) To expand a product of two or more algebraic expressions, typically binomials.

(obsolete) To defile; to soil.

To prevent (something) from being accomplished. / To prevent (someone) from accomplishing something. / To blunt; to dull; to spoil. / (obsolete) To tread underfoot; to trample.

Failure when on the point of attainment; defeat; frustration; miscarriage. / One of the incorrect answers presented in a multiple-choice test.

(hunting) The track of an animal.

simple past tense and past participle of foil

(architecture) Having a foil.

plural of foil

Third-person singular simple present indicative form of foil

present participle of foil