doo·zy or doo·zie 
(dzē)
(dzē)n. pl. doo·zies
Slang
Slang
Something extraordinary, impressive, or unique: a doozy of a hailstorm.
[Probably alteration of DAISY, splendid person or thing (perhaps influenced by the name of Eleonora Duse (1858-1924), Italian actress).]