"Insubstantiality" is a word in ENGLISH

Consisting of air; resembling, or partaking of the nature of air. Hence: Unsubstantial; unreal.

Unsubstantial; unreal; as, shadowy honor.

Not real; unsubstantial; fanciful; ideal.

That which is vain; anything empty, visionary, unreal, or unsubstantial; fruitless desire or effort; trifling labor productive of no good; …

The quality or state of being vain; want of substance to satisfy desire; emptiness; unsubstantialness; unrealness; falsity.

Something unsubstantial, fleeting, or transitory; unreal fancy; vain imagination; idle talk; boasting.

Unreal; unsubstantial; vain; whimsical.