loo /luː/noun 9verb 4exclamation 1forms 3 noun9 •(UK, informal) A lavatory: a room used for urination and defecation.Ensure that the tents are well-sited and clean, rubbish bins empty, and that the loos have toilet paper. — 2006 •(UK, informal) A toilet: a fixture used for urination and defecation. •(US, slang) A lieutenant.I asked my loo to let me escort you in. I wanted a moment to thank you personally.” “There's no need.” “So you said before, but there is. And was. I'll take you in to Lieutenant Ricchio.” — 2012 •(India) A hot dust-bearing wind found in Bihar, Uttar Pradesh and the Punjab.It was a pitchy black night, as stifling as a June night can be, and the loo, the red-hot wind from the westward, was booming among the tinder-dry trees and pretending that the rain was on its heels. — 1888 •A game of lanterloo. •The penalty paid to the pool in lanterloo for breaking certain rules or failing to take a trick. •An act that prompts such a penalty. •(figurative) Any group of people. •(no longer used) A half-mask, particularly (historical) those velvet half-masks fashionable in the 17th century as a means of protecting women's complexion from the sun.Loo Mask. An half Mask. — 1685 verb4 •To beat in the card game lanterloo.He was seldom indeed without two good trumps, and therefore almost invariably loo'd those who stood. — 1847 •To pay a penalty to the pool for breaking certain rules or failing to take a trick in lanterloo. •(dialect, figurative) To pay any penalty to any community. •(dialect) To urge on with cries of loo or (figuratively) by other shouting or outcry.And therefore next uncouple either Hound [sc. George Monck and Prince Rupert], And loo them at two Hares ere one be found. — 1667 exclamation1 •A cry to urge on hunting dogs.Edg. Pilicock sate on pelicocks hill, a lo lo lo. — 1603 formslooed · looing · loos