Etymology

The Australian slang is from a racehorse called Drongo (foaled 1921, retired 1925) which ran poorly, and by transferrance anyone slow-witted or clumsy became a drongo. (Reference: Bill Wannan, Australian Folklore, Lansdowne Press, 1970, reprint 1979 ISBN 0-7018-1309-1, entry for "Drongo", page 200.)

The horse was apparently named for the bird the Spangled Drongo (Dicrurus bracteatus).

Noun

1. Various birds of the family Dicruridae.
2. fool, idiot.