Definition: lacking definition or definite content
Usage: nebulous reasons; unfixed as were her general notions of what men ought to be- Jane Austen
Main entry: nebulose, nebulous, cloudy
Definition: lacking definite form or limits
Usage: gropes among cloudy issues toward a feeble conclusion- H.T.Moore; nebulous distinction between pride and conceit
Definition: of or relating to or resembling a nebula
Usage: the nebular hypothesis of the origin of the solar system