Toilet
Restroom, Bathroom
noun
*Ahem.* This is the place of convenience. What place above all others do you want to be convenient? Just in case, you know... that would be the toilet. You might also call it the lavatory, the restroom, or the bathroom.
This word is casual and sounds gruff, so you won't see it on offical signs or hear it in polite conversation. It's worth knowing so that you'll understand it in casual speaking and writing, though.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well. Just watch out for the rendaku.
便所のにおい
toilet smell
便所の出入り口
bathroom entrance
便所のドア
toilet door
やばい。便所サンダルで学校に来ちゃった！
Oh snap. I came to school in toilet sandals!
ちょっとコンビニの便所行ってくるわ。
I'm going to a convenience store bathroom real quick.
「便所」っていう言葉はちょっと下品ですよ。
The word 便所 sounds a bit vulgar.