Synonyms of insoluble

insoluble

adjective

(ˌ)in-ˈsäl-yə-bəl 

as in impossible

incapable of being solved or accomplished

the seemingly insoluble mystery concerning the identity of the people who built these ancient structures

Synonyms & Similar Words

• impossible
• hopeless
• unlikely
• problematic
• insolvable
• unsolvable
• insuperable
• futile
• unattainable
• impractical
• unrealizable
• undoable
• useless
• incredible
• absurd
• unworkable
• impracticable
• unusable
• questionable
• infeasible
• dubious
• improbable
• suspect
• inconceivable
• debatable
• unfeasible
• disputable
• suspicious
• implausible
• fishy
• unthinkable
• shaky
• unimaginable
• unbelievable
• doubtful
• ridiculous
• far-fetched
• doubtable
• outlandish
• shady
• preposterous
• fantastic

Antonyms & Near Antonyms

• soluble
• possible
• feasible
• workable
• practical
• achievable
• attainable
• useful
• applicable
• functional
• reasonable
• usable
• resolvable
• practicable
• working
• realizable
• probable
• serviceable
• likely
• doable
• acceptable
• plausible
• conceivable
• credible
• believable

Example Sentences

Recent Examples of insoluble

The company says its indigo process uses soluble precursors that oxidize into insoluble pigment within the textile, avoiding the chemical reduction step used in conventional indigo dyeing. — Alexandra Harrell, Footwear News, 30 Oct. 2026

But this approach provides only symptomatic relief to the overarching and insoluble crisis produced by his totalitarianism. — Jieun Baek, Foreign Affairs, 30 Oct. 2026

With her knack for devising novel solutions to seemingly insoluble problems, no one was better suited for the job. — Dean Robbins, Space.com, 18 Oct. 2026

Both soluble and insoluble fiber are important for gut health. — Jackie Flynn Mogensen, Scientific American, 5 Oct. 2026