spot·ter / ˈspätər/ • n. inf. a person employed by a company or business to keep watch on employees or customers. ∎ an aviator or aircraft employed in locating or observing enemy positions: [as adj.] spotter planes. ∎ a person who observes or assists a gymnast or weightlifter during a performance or practice in order to minimize the chance of injury to the gymnast or weightlifter.