ETYMOLOGY
corruption of ‘dubious’
EXAMPLE
“…The Squire,” said he, ” hadn’t a-made him no proposal at all, and was duberous if his charackter would serve. Now, says I to myself, seeing as how the cat jumps, if so be as I steps in, before nothing and scrape of pen, where ‘s the harm ? …”
From: Lawrie Todd, or, The Settlers in the Woods
By John Galt, 1830
Lexicophilia 