[ uhn-suh b-stan-shuh l ]
/ ˌʌn səbˈstæn ʃəl /


not substantial; having no foundation in fact; fanciful; insubstantial: an unsubstantial argument; unsubstantial hopes.
without material substance: an unsubstantial ghost.
lacking material substance; materially paltry: an unsubstantial dinner of bread and cheese.
lacking strength or solidity; flimsy: an unsubstantial wall of cardboard.

Origin of unsubstantial

late Middle English word dating back to 1425–75; see origin at un-1, substantial

OTHER WORDS FROM unsubstantial

un·sub·stan·ti·al·i·ty, nounun·sub·stan·tial·ly, adverb
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for unsubstantial

British Dictionary definitions for unsubstantial

/ (ˌʌnsəbˈstænʃəl) /


lacking weight, strength, or firmness
(esp of an argument) of doubtful validity
of no material existence or substance; unreal

Derived forms of unsubstantial

unsubstantiality, noununsubstantially, adverb
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012