nebulous

adjective

neb·​u·​lous ˈne-byə-ləs 

1

: of, relating to, or resembling a nebula : nebular

2

: indistinct, vague

… this nebulous thing called jazz.

—Josef Woodard

… the nebulous region between mere suspicion and probable cause

—W. R. LaFave & J. H. Israel

The plan is too nebulous.

nebulously adverb

nebulousness noun

Did you know?

Nebulous may sound otherworldly—after all, it’s related to nebula, which refers to an interstellar cloud of gas or dust—but its mysteriousness is rooted in more earthly unknowns. Both words ultimately come from Latin nebula, meaning “mist, cloud,” and as far back as the 14th century nebulous could mean simply “cloudy” or “foggy.” Nebulous has since the late 17th century been the adjective correlating to nebula (as in “nebulous gas”), but the word is more familiar in its figurative use, where it describes things that are indistinct or vague, as when Teju Cole wrote of an avant-garde photographer who viewed photography as existing “neither in the camera nor in the printed photograph, but in a more nebulous zone.”

Synonyms of nebulous

• ambiguous
• cryptic
• obscure
• dark
• vague

Examples of nebulous in a Sentence

These philosophical concepts can be nebulous.

made nebulous references to some major changes the future may hold

Recent Examples on the Web

There remains the question of whether vibe coding works in the artistic space, where the goal is not simply a functional end product but a more nebulous, subjective piece of art. —Steven Zeitchik, HollywoodReporter, 23 June 2026

Partnership seeks clearer reflection as the intuitive Moon in your 7th House of Partnership opposes nebulous Neptune in your 1st House of Identity, so connection and self-image pull in different directions. —Tarot.com, Sun Sentinel, 22 June 2026

Jackson’s connection to the park beyond the name is nebulous. —Michael Peregrine, Chicago Tribune, 21 June 2026

As a ritual romanticized for generations as one of the most significant events of a person’s life, the modern wedding tends to provoke a nebulous kind of introspection separating it from its most notable counterparts. —Bobby Finger june 16, Literary Hub, 16 June 2026

Word History

Etymology

Latin nebulosus misty, from nebula

First Known Use

1674, in the meaning defined at sense 1

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Kids Definition

nebulous

adjective

neb·​u·​lous ˈneb-yə-ləs 

1

: of, relating to, or resembling a nebula

2

: not clear or sharp : vague

nebulously adverb

nebulousness noun