unsubstantial

Lacking material substance; insubstantial.

Lacking firmness or strength; flimsy.

Lacking basis in fact.

Not substantial; not solid: as, unsubstantial air. Not real; not having substance; imaginary; illusive: as, unsubstantial forms. Not having good substance; not strong or stout: as, an unsubstantial building; unsubstantial cloth.

Not giving substance or strength; weak; not strengthening or invigorating.

Lacking in matter or substance; visionary; chimerical.

Alternative form of insubstantial.

lacking material form or substance; unreal