definition of
insubstantial

[1] #1 insubstantial a. [unsubstantial, unreal] lacking material form or substance; unreal; "as insubstantial as a dream"; "an insubstantial mirage on the horizon". wn

[2] #2 insubstantial s. [jejune] lacking in nutritive value; "the jejune diets of the very poor". wn