Fleeting, shifting; light, airy, unsubstantial.

In the classical theory of the elements: governed by or associated with the air; (hence) volatile, delicate. Obsolete.

Like air in its lightness and buoyancy. Of a material: light and delicate, as if capable of floating in the air. Also of a thing: light and…

of aerial lightness, light as air.

(cf. blow, v.1 12a), susceptible to the influence of a current of air, hence fragile; also figurative.

Extremely light (in various senses); esp. insubstantial, inconsequential; very subtle or delicate.