[on the Q.T.] {adv. phr.}, {informal} Secretly; without anyone's knowing. * […]

[on the road] {adv.} or {adj. phr.} 1. Traveling; moving from […]

[on the ropes] {adv.} or {adj. phr.} 1. Against the ropes […]

[on the run] {adv.} or {adj. phr.} 1. In a hurry; […]

[on the safe side] {adv. phr.} Provided for against a possible […]

[on the shelf] {adv.} or {adj. phr.}, {informal} Laid aside; not […]

[on the side] {adv. phr.}, {informal} 1. In addition to a […]

[on the sly] {adv. phr.} So that other people won't know; […]

[on the spot] {adv.} or {adj. phr.} 1. or [upon the […]

[on the spur of the moment] {adv. phr.} On a sudden […]