[OIC] "Oh, I see"

[oik] {n.} Someone of a low social standing (derogatory).

[oil] See: [POUR OIL ON TROUBLED WATERS].

[oil the wheels] See: [GREASE THE WHEELS].

[ointment] See: [PLY IN THE OINTMENT].

[old] See: [CHIP OFF THE OLD BLOCK], [COMFORTABLE AS AN OLD […]

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

[old bill] or [the old bill] {n.} A policeman or the […]

[old boy] or [old chap] {n.}, {chiefly British} One of the […]

[old boy network] {n. phr.} A system whereby men who went […]