See a man about a horse

[PussyCat]

Any general business that needs attending to that you may not care to discuss whith the present party.

[Tina]

A discreet way to leave the table at a restaurant to go to the restroom; derived from a 1940s black-and-white film (sorry, cannot recall the name) where an actor literally says it as he leaves a table to see a man at another table about a horse.

[Sonia]

It means to politely excuse yourself from a situation to go to the restroom or buy a drink. It originated from men disappearing to go bet on horse or dog races. See a man about a dog means the same thing.

[Couch Potatoe]

To take a piss.

[PussyCat]

Used by males to politely excuse themselves to the washroom for number one purposes.
While reinforced by both of these examples:
Any general business that needs attending to that you may not care to discuss whith the present party.
We can meet for lunch on Tuesday, since Ill be in the area; I have to see an man about a horse.
by moth17 Jul 5, 2005
2. see a man about a horse 271 up, 73 down
A discreet way to leave the table at a restaurant to go to the restroom; derived from a 1940s black-and-white film (sorry, cannot recall the name) where an actor literally says it as he leaves a table to see a man at another table about a horse.
Excuse me, I have to see a man about a horse.
The origins date back to the days of the Not-Quite-So-Wild-Yet-Still-Wild Enough Old West. When at the local drinking establishment (read at the Saloon) the horse trough was closer to the entrance of the building (usually directly attached) than the outhouses which were generally situated out back. And thus a slang term was born. And of course MOST people had enough common decency to only use the trough for number one.

[Jessica]

urination by a male

[Becky]

going on a sexual escapade with a man hung like a horse