One who works only half the usual time, especially (historical) a pupil in an elementary school allowed to be absent half the school-day at some employment.

plural of half-timer

(slang) An elderly person.

plural of short-timer

A chess clock.

plural of chess timer

(informal) A person who devotes themselves to having fun; a hedonist.

plural of good-timer

plural of old timer

An instrument for measuring the passage of time by the passage of sand through a narrow opening.