Privy (3)
I believe the answer is:
loo
'privy' is the definition.
(I know that loo is a type of privy)
This is all the clue.
(Other definitions for loo that I've seen before include "The little room - card game" , "Card game; the 'smallest room'" , "In which one goes" , "Toilet (informal)" , "bog" .)