[off-key] {adj.}, {informal} 1. Not proper; queer. * /When George told […]

[off-the-cuff] {adj.}, {informal} Not prepared ahead of time. - Used of […]

[offbeat] {adj.}, {informal} Nonconventional; different from the usual; odd. * /Linguistics […]

[offhand] {adj.} {adv.} 1. Informal; casual; careless. * /Dick found Bob's […]

[old as the hills] {adj. phr.} Very old; ancient. * /"Why […]

[old hat] {adj.}, {informal} Old-fashioned; not new or different. * /By […]

[on board] (2) {adv.} or {adj. phr.} On a ship. * […]

[on call] {adj. phr.} 1. Having to be paid on demand. […]

[on cloud nine] {adj. phr.}, {slang} Too happy to think of […]

[on deck] {adv.} or {adj. phr.} 1. On a floor of […]