The state of being idle; inactivity. / The state of being indolent; indolence. / Groundlessness; worthlessness; triviality; vanity; frivolity.

(law, of a name) wrongly spelled, but sufficiently correct to identify someone.

An ideogram.

(metaphysics) An idea separated from a complex object, or from other ideas which naturally accompany it; as the solidity of marble when contemplated apart from its color or figure.

An artificial language, created by Waldemar Rosenberger in 1902, partially derived from Volapük, with a vocabulary consistently selected on the basis of the maximum internationality of the roots.

One who worships idols; (historical) a pagan.

(physics) the equation of state of an ideal gas

(physics) a hypothetical gas, whose molecules exhibit no interaction, and undergo elastic collision with each other and with the walls of the container

(dated, psychology, now derogatory) The state or condition of being an idiot; the quality of having an intelligence level far below average; mental retardation; intellectual disability.

(informal) To not know; to have no idea.