Green’s Dictionary of Slang

loo n.¹

the lavatory.

[1782		W. Mason letter in Harcourt Harcourt Papers VII 78: I am glad your Lieux are likely to become sweet, but I still fear about them. I always suspected that the smell came from the great drain under the house [...] I am myself employed in constructing a lieu here [...] I trust it will turn out a paragon, both for sweetness, utility, & cheapness].
1940		N. Mitford Pigeon Pie 27: In the night when you want to go to the loo.
1950		A. Christie Murder Is Announced (1958) 154: We all went to the lou, didn’t we? [...] And I washed my hands.
1968		G. Slatter Pagan Game (1969) 65: He hated English novels which called it the loo.
1972		A. Chipper Aussie Swearers Guide 33: You can stay at home, get shickered [...] and have a good chunder in your own loo, la-la, toot or diddy.
1977		S. Berkoff East in Decadence and Other Plays (1985) 54: In either case I can shove it in the loo!
1980		M. Melamu ‘Bad Times, Sad Times’ in Mutloatse Forced Landing 41: I’ve no choice but to irrigate the outside of the loo, while the landlord’s mongrel, Spotty, playfully tugs at my trouser-pipe. Ag, man, voetsek!
1986		R.G. Barrett Godson 18: ‘I had to go to the loo’.
1989		in G. Tremlett Little Legs 75: I always used their loo.
1994		E. St Aubyn Some Hope 317: When we took gear at parties, all we saw was the inside of the loos.
2000		R.G. Barrett Leaving Bondi (2013) [ebook] ‘I’ll just go to the loo’.
2005		H. Mantel Beyond Black 112: I want to go to the loo.
2011		Observer New Review 7/4: Will you be calling if you think he needs the loo?
2011		IOL News (Western Cape) 11 May 🌐 Malema steps into open loo saga [...] saying individuals in the council and not the ANC gave people open toilets.
2108		M. McGrath Pie & Mash 9: Ted Willets who once painted lady Di’s loo.

In phrases