This adjective used to describe something excellent or of particular note is of unknown origin, although it may stem from a now obsolete slang term. It first appears in 1903 in Kleberg’s Slang Fables From Afar:
As soon as the races were billed he began to evolve schemes—one doozy scheme followed the other.
While the origin is not known for certain, the best guess is that it is a variant of an earlier slang term daisy, also meaning something excellent. From Samuel Foote’s 1757 The Author:
Oh daisy; that’s charming.
And from F.H. Burnett’s Little Lord Fauntleroy of 1887:
She’s the daisiest gal I ever saw! She’s—well she’s just a daisy, that’s what she is.
There are a couple of popular etymologies for doozy floating about that are worth mentioning.
Car enthusiasts often maintain that doozy is after the Duesenberg line of automobiles. Unfortunately for this story, the Duesenberg Automobile & Motors Company was not founded until 1913, a decade after doozy appears in print. Duesenbergs may have been affectionately known as doozies, but this is a link with an existing slang term, not a new coinage.
The second has doozy as an eponym for the Italian actress Eleonora Duse (1858-1923). The timing is right and she was quite famous in her day, but there is no evidence linking her with doozy.
(Source: Oxford English Dictionary, 2nd Edition)
Copyright 1997-2015, by David Wilton