insubstantial

adjective

in·​sub·​stan·​tial ˌin(t)-səb-ˈstan(t)-shəl 

: not substantial: such as

a

: lacking substance or material nature

b

: lacking firmness or solidity : flimsy

insubstantiality

ˌin(t)-səb-ˌstan(t)-shē-ˈa-lə-tē 

noun

Synonyms

• cobwebby
• filmy
• flimsy
• frothy
• gauzy
• gossamer
• gossamery
• sleazy
• unsubstantial

Examples of insubstantial in a Sentence

Their contribution to the fund was insubstantial.

as insubstantial as a ghost

Recent Examples on the Web

Trump and Musk are truly onions made of glass: shiny orbs of one insubstantial layer over another, with nothing in the center, liable to be shattered under the slightest pressure. —Thomas G. Moukawsher, MSNBC Newsweek, 14 Apr. 2025

Nineteen is certainly a lot lower than 42, but, um, 19 over the course of 94 episodes of television is not exactly and insubstantial amount. —Jordan Hoffman, EW.com, 28 Apr. 2025

YouTube videos as addictive and insubstantial as cotton candy needed my immediate intervention. —Michael Alcée, Hartford Courant, 13 Apr. 2025

Bashar was an ophthalmology student in London, a weak-chinned introvert who was widely seen as a bit insubstantial. —Jon Lee Anderson, The New Yorker, 27 Jan. 2025

Word History

Etymology

probably from French insubstantiel, from Late Latin insubstantialis, from Latin in- + Late Latin substantialis substantial

First Known Use

1607, in the meaning defined above

Rhymes for insubstantial

• circumstantial
• unsubstantial
• substantial

Kids Definition

insubstantial

adjective

in·​sub·​stan·​tial ˌin(t)-səb-ˈstan-chəl 

: not substantial: as

a

: not real : imaginary

insubstantial differences

b

: not firm or solid

a flimsy insubstantial shelf

insubstantiality

-ˌstan-chē-ˈal-ət-ē 

noun