i Register
In some senses, lavvy is marked as slang, UK. Watch for register when choosing this word.
noun
A lavatory: a room used for urination and defecation.
It must be great getting up during the night and not having to put a coat on over your jammies to visit the lavvy on the half-landing – especially in the winter when it's below zero.
When I had to go to the lavvy there I always had to use that stiff, scratchy, smelly, lavvy paper she always said she 'put for the 'young ladies' - sniff'.
A toilet: a fixture used for urination and defecation.