1. In 16-19 th century England, the backside, the posterior. See ass for synonyms.
2. From the 1930s onward, the female genitals. See vagina for synonyms.
3. To prat for , to bend over to assume a receptive position for anal intercourse.
4. In Britain, a mild term of abuse for a fooll or an incompetent fool. ' That silly prat! '