Not ponderable; without sensible or appreciable weight; incapable of being weighed.
Difficult or impossible to comprehend or evaluate.
An imponderable question.
A factor that cannot be anticipated.
An imponderable substance or body; specifically, in the plural, a name formerly applied to heat, light, electricity, and magnetism.
Lacking depth or substance; insubstantial, thoughtless, vague.
Of a thing: covered or hidden by vapour, fog, or mist.
Of a place: filled with vapour; foggy, misty.
Breathing out or giving off vapour.
Of or relating to vapour; also, having the characteristics or consistency of vapour.
Of clothes or fabric: thin and translucent; filmy, gauzy.