unsubstantial

adjective

un·​sub·​stan·​tial ˌən-səb-ˈstan(t)-shəl 

: not substantial : lacking substance, firmness, or strength

unsubstantial shadows

an unsubstantial diet

unsubstantiality

ˌən-səb-ˌstan(t)-shē-ˈa-lə-tē 

noun

unsubstantially

ˌən-səb-ˈstan(t)-sh(ə-)lē 

adverb

Synonyms of unsubstantial

• spiritual
• incorporeal
• metaphysical
• insubstantial
• immaterial
• supernatural

Examples of unsubstantial in a Sentence

as thin and unsubstantial as the wind

an unsubstantial child who was unfit to play sports of any kind

Recent Examples on the Web

Yet for all its craft, the film remains airy and unsubstantial, never quite rising to the full potential of its premise. — Leila Latif, IndieWire, 31 Aug. 2025

Roadmaps are frequently high-level and unsubstantial. — Peter Bendor-Samuel, Forbes.com, 19 June 2026

The algorithm fed the Giants pitcher a savory yet unsubstantial diet of short-form content. — Justice Delos Santos, Mercury News, 31 Mar. 2025

Then again … This really does sum up Reeves’s unsubstantial performance as Jonathan Harker, whose new client is definitely up to no good. — Tim Grierson, Vulture, 18 Oct. 2025

Word History

First Known Use

15th century, in the meaning defined above

Rhymes for unsubstantial

• circumstantial
• insubstantial
• substantial

Kids Definition

unsubstantial

adjective

un·​sub·​stan·​tial ˌən(t)-səb-ˈstan-chəl 

: lacking substance, firmness, or strength