Orig: the famous Monty Python sketch about the penguin on the television set. Graham Chapman forgot his line/lost his place, and improvised with the word 'burma'.
cleese: penguins don't come from next door they come from the Antarctic!
cleese: .....why'd you say 'burma'
chapman: I panicked
In order to officially qualify as a burma, the woman must meet at least two of the following three criteria:
1. She must be old.
2. She must be fat.
3. She must be mean, or have an otherwise exceptionally terrible personality.
The male equivalent of this word is burmo.
Have you ever ever met Frank's mom? Such a burma, dude.