The disctinctive purple vagina of a black female. Derived from the purple colour of a plum and the word poon.
I entered an ebony porn site looking for poon, but I only found ploon.
by Fernando Leon September 24, 2008
by Peter Santafe January 08, 2005
Someone who is usually fairly intelligent but does something moronic or out of character would be a ploon.
Ryan thought the time was 3am because the clock stopped working even though it was still sunny, what a ploon.
by Mancazza March 18, 2011