A spittoon is a container that people use to spit into, especially indoors.
Spittoons are not very common anymore, and some people might find them gross.
Examples:
The cowboy spat into the spittoon.
The old saloon had a lot of spittoons.
The spittoon was full of gross stuff.
The spittoon was so full, it looked like a small pond.
In the olden days, spittoons were everywhere, but now they are rare.
The spittoon was shiny and made of metal.