Doozy
Etymology
American slang from the early 1900s, and its origin is disputed. Candidates include an alteration of "daisy" (long used to praise something excellent), possible influence from the celebrated actress Eleonora Duse, and a popular link to the luxurious Duesenberg car ("Duesy"). Since the word appears to predate the car’s fame, that last connection is likely a folk etymology rather than the source.
noun · /DOO-zee/
Something extraordinary of its kind, whether remarkably good or remarkably bad.
What it names
The standout example — the storm, the exam, the excuse that is memorably extreme in either direction.
Example
The final question on the exam was a real doozy — half a page just to state it.
Related idea
A humdinger leans positive, an outstanding specimen; a doozy can cut either way, good or catastrophic.
See also