What is see a man about a horse origin?

The phrase "See a man about a horse" originated in the late 19th century in America. It was used as a polite way for someone to excuse themselves to attend to a personal matter without disclosing the nature of that matter.

There are a few theories as to the exact origin of the phrase. One theory suggests it may have originated from the practice of men going to the stable to check on their horses before making a transaction or conducting business. Another theory suggests it may have come from the world of horseracing, where jockeys and trainers would use the phrase to excuse themselves to attend to a horse before a race.

Regardless of its exact origin, the phrase has become a popular idiom in English and is often used humorously or ironically to indicate a vague or non-specific purpose or to avoid revealing too much information about one's plans.