Mostly means over the top, loud, colourful.
Can be applied to objects or people.
Often associated with gay men, but does not MEAN "gay" as some previous additions seem to imply.
2. Geoff is being very flamboyant tonight.
It is also often used in association to the word "gay" as in a fairy, fruity guy, homosexual.
Used more towards men than woman.
Which in a way makes sense since most gay men are very flamboyant, like Jeffrey star for instance, with his hot pink hair and super long eye lashes.