Pronunciation: (un"sub-stan'shul), [key]
1. not substantial; having no foundation in fact; fanciful; insubstantial: an unsubstantial argument; unsubstantial hopes.
2. without material substance: an unsubstantial ghost.
3. lacking material substance; materially paltry: an unsubstantial dinner of bread and cheese.
4. lacking strength or solidity; flimsy: an unsubstantial wall of cardboard.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.