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Synonyms

insubstantial

American  
[in-suhb-stan-shuhl] / ˌɪn səbˈstæn ʃəl /

adjective

  1. not substantial or real; lacking substance.

    an insubstantial world of dreams.

  2. not solid or firm; weak; flimsy.

  3. not substantial in amount or size; inconsiderable.

    an insubstantial sum.


insubstantial British  
/ ˌɪnsəbˈstænʃəl /

adjective

  1. not substantial; flimsy, tenuous, or slight

  2. imaginary; unreal

"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

Other Word Forms

  • insubstantiality noun
  • insubstantially adverb

Etymology

Origin of insubstantial

From the Late Latin word insubstantiālis, dating back to 1600–10. See in- 3, substantial

Explanation

Insubstantial is an adjective that means lacking form, substance or nutritional value. If you're really hungry, a bowl of clear broth will seem pretty insubstantial. If there is insubstantial evidence to convict an accused criminal, he will be set free. In the office, insubstantial expenses should be paid out of the petty cash draw. A thin blouse is too insubstantial to be worn in this cold weather. And a candy bar makes an insubstantial lunch — a sandwich and fruit would be more nutritious.

Keep Reading on Vocabulary.com

Vocabulary lists containing insubstantial

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Many who do, such as Dan Aykroyd, say very nice things that are insubstantial; Ryan Reynolds is one of the few who comment critically on Mr. Chase’s comedic style, which is highly enlightening.

From The Wall Street Journal • Dec. 30, 2025

The UN's cultural agency said that despite "significant growth in production", industries across the content were hindered by issues such as piracy, insubstantial training opportunities and a lack of official film institutions.

From BBC • Aug. 2, 2024

It’s a majority white district, with not insubstantial Asian and Latino populations.

From Los Angeles Times • Apr. 26, 2024

The ads that failed were ultimately insubstantial, or otherwise objectionable.

From Slate • Feb. 12, 2024

Even as a young man, Newton was impatient with insubstantial questions, such as whether light was “a substance or an accident,” or how gravitation could act over an intervening vacuum.

From "Cosmos" by Carl Sagan