one-on-one adj 1: directly between two individuals; "one-on-one instruction" 2: being a system of play in which an individual defensive player guards an individual offensive player; "one-on-one defense" [syn: {man-to-man}] adv : (of two persons) in direct encounter; "preferred to settle the matter one-on-one"; "interviewed her person-to-person" [syn: {person-to-person}]