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 other-worldly—after all, it’s related to nebula, which refers to a distant galaxy or 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 Jack London wrote of “ideas that were nebulous at best and that in reality were remembered sensations.”

Synonyms

• ambiguous
• arcane
• cryptic
• dark
• deep
• Delphic
• double-edged
• elliptical
• elliptic
• enigmatic
• enigmatical
• equivocal
• fuliginous
• inscrutable
• murky
• mysterious
• mystic
• obscure
• occult
• opaque

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

Dan, Danny, Amanda, Savannah, and Michelle land on a more nebulous seafood theme tied to the water surrounding them, and Danny will be executive chef, Michelle will be front of house, and Dan, Amanda, and Savannah will be line cooks. —Roxana Hadadi, Vulture, 8 May 2024

The operatives are there on behalf of the nefarious man running the nebulous spy organization The Division, Ritter (Bryan Cranston), who is growing tired of the failures of those who serve him. —Mark Meszoros, Hartford Courant, 1 Feb. 2024

Even the most media-stringent parents get submerged by elementary school in a nebulous cloud. —Kendra Thomas, TIME, 5 June 2024

Her comment had interrupted a moment of happiness with a nebulous dread of the future. —Katie Reilly, Vox, 4 June 2024

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