- leadoff⇄adj. that begins or leads off.
Ex. a leadoff witness, a leadoff batter. - leadoff⇄leadoff, noun, adjective.
- leadoff⇄noun 1. an act of beginning or starting something.
Ex. The chairman was responsible for the leadoff of the campaign.
2. (Baseball.) the first player of the batting order or the first to come to bat in an inning.