Meaning of insubstantial

(adj) lacking material form or substance; unreal; "as insubstantial as a dream"; "an insubstantial mirage on the horizon"

lacking in nutritive value; "an insubstantial and unsatisfying meal"

lacking solidity or strength; "a flimsy table"; "flimsy construction"; "vinyl siding has become the standard-bearer for cheap, insubstantial construction"