Lacking substance or reality. See Synonyms at immaterial.(adjective)
Not firm or solid; flimsy.(adjective)
Negligible in size or amount.(adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "insubstantial" in a sentence
"Is it possible that the fashion industry, long patronized as a realm of the ephemeral and insubstantial, is the real bellwether for future ideas of “ownership” of creative content?"
"Both start with an idea, something insubstantial, that is transformed into an artifact that can influence the world and other people."
"That just won't work, particularly when the Democrats aren't very good at battling the Republicans in close combat and the Republicans can make those who stay above the fray seem lightweight and insubstantial, which is what they've managed to do."