Nebulous
adjective
lacking definition or definite content; ; - Jane Austen
“nebulous reasons”
Similar: unfixed
adjective
lacking definite form or limits; - H.T.Moore
“gropes among cloudy issues toward a feeble conclusion”
Similar: cloudy, nebulose
adjective
of or relating to or resembling a nebula
“the nebular hypothesis of the origin of the solar system”
Similar: nebular