Synonyms of impossible

impossible

adjective

(ˌ)im-ˈpä-sə-bəl 

as in unlikely

incapable of being solved or accomplished

the seemingly impossible problem of world hunger

fitting everything in my backpack seemed an impossible task

Synonyms & Similar Words

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

Antonyms & Near Antonyms

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

Example Sentences

Recent Examples of impossible

Besides the new material itself, another advantage is showing that molecular engineering can custom-build layered materials to combine features that used to be impossible to mix, like rock-hard strength and extreme heat insulation. — Mrigakshi Dixit, Interesting Engineering, 18 Sep. 2026

There is a sweetness and an elegance to her, Michele says, as well as an exuberance that’s impossible to counterfeit. — Alessandra Codinha, Vogue, 18 Sep. 2026

Figuring out from symptoms alone whether your child has COVID-19 is often impossible. — Ann Sheehan, The Conversation, 18 Sep. 2026

Rescuers threw a rope, but with frostbitten hands and shifting ice, escape was impossible. — Carly Tagen-Dye, PEOPLE, 18 Sep. 2026