(literally) Having two faces or plane surfaces. / Deceitful, duplicitous. / Hypocritical.

(nautical) The practice of having two alternate watches aboard a ship or vessel.

In a two-faced manner.

Consisting of two layers or two strands. / (textile fabrics) Consisting of two webs woven into one another. / (manufactured articles, linen) Consisting of two thicknesses.

Having two colours or shades. / Giving two different sounds, either alternately or simultaneously.

comprising two pieces

Having two sides, bilateral. / Reversible. / (algebra) Whose salient properties apply when (the specified object) appears on either side of a given binary operator.

Using or designed for use by both hands at once. / Involving, or designed for use by, two people. / Ambidextrous. / Having two hands. / (UK, slang, dated) Good with one's fists; able to fight well.

(US, slang) Twenty-five cents, or a quarter.

A garment consisting of two separate parts; especially such a swimsuit