[on the wing] {adv.} or {adj. phr.} 1. In the air; […]

[on time] {adv.} or {adj. phr.} 1. At the time arranged; […]

[on top] {adv.} or {adj. phr.}, {informal} In the lead; with […]

[on top of the world] or [sitting on top of the […]

[on trial] {adv.} or {adj. phr.} 1. For testing or trying […]

[one and the same] {adj. phr.} The same; identical. * /Erle […]

[one up] {adj. phr.} Having an advantage; being one step ahead, […]

[one-horse] {adj. phr.} Insignificant; modest; provincial. * /Arnold's business is a […]

[open and aboveboard] {adj. phr.} Honest. * /Jacob felt that the […]

[open-minded] {adj.} Having no dogmatic or biased views on matters of […]