insubstantial

1 being of a material lacking in sturdiness or substance an insubstantial carton that could not possibly stand up during long-distance shipping Synonyms cobwebby, filmy, frothy, gauzy, gossamer, gossamery, flimsy, sleazy, unsubstantialRelated Words dainty, delicate, fine; feeble, fragile, frail; diaphanous, sheer, transparentNear Antonyms durable, knockabout, lasting, tough; coarse, heavy, rough, rudeAntonyms sturdy, substantial

2 not composed of matter energy is insubstantial Synonyms bodiless, ethereal, formless, incorporeal, immaterial, nonmaterial, nonphysical, spiritual, unbodied, unsubstantialRelated Words metaphysical, psychic (also psychical), supernatural; impalpable, insensible, intangible, invisible; airy, diaphanous, gaseous, gossamery, tenuous, thin, vaporous, wispishNear Antonyms animal, carnal, fleshly; detectable, discernible (also discernable), noticeable, observable, palpable, sensible, tangible, visible; bulky, heavy, massive, solidAntonyms bodily, corporeal, material, physical, substantial