noun.
One who supports or upholds; a supporter; a backer.
noun.
One who or that which stops or restrains.
noun.
One who stays or remains: as, a stayer at home.
noun.
One who has sufficient endurance to hold out to the end; a person or an animal of staying qualities, as in racing or any kind of contest; one who does not readily give in through weakness or lack of perseverance.
the GNU version of the Collaborative International Dictionary of English
noun.
One who upholds or supports that which props; one who, or that which, stays, stops, or restrains; also, colloquially, a horse, man, etc., that has endurance, as in a race.