A burrahobbit is a hobbit
that is a burglar, and realizes in midword that introducing himself as a burglar is likely to get him put quickly into a stewpot.
"Blimey, Bert, look what I've copped!" said William.
"What is it?" said the others coming up.
"Lumme, if I knows! What are yer?"
"Bilbo Baggins, a bur--a hobbit," said poor Bilbo, shaking all over, and wondering how to make owl-noises before they throttled him.
"A burrahobbit?" said they a bit startled. Trolls are slow on the uptake, and mighty suspicious about anything new to them.
"What's a burrahobbit got to do with my pocket, anyways?" said William.