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

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

But, taking these study findings from here all the way down the drug development pipeline to where there’s a safe and effective new drug on the market is expected to take a long time and a not insubstantial amount of money. —New Atlas, 21 Jan. 2025

With a not insubstantial piece of Mexico’s economy reliant on production stateside, a cessation of those inflows will logically impoverish a big number of those formerly sustained directly by remittances. —John Tamny, Forbes, 4 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