impossible

incapable of being solved or accomplished the seemingly impossible problem of world hunger fitting everything in my backpack seemed an impossible task Synonyms hopeless, insoluble, insolvable, insuperable, unattainable, undoable, unrealizable, unsolvable Related Words impracticable, impractical, infeasible, unusable, unworkable; debatable, disputable, doubtable, doubtful, dubious, far-fetched, fishy, improbable, problematic (also problematical), questionable, shady, shaky, suspect, suspicious, unfeasible, unlikely; implausible, inconceivable, incredible, unbelievable, unimaginable, unthinkable; futile, useless; absurd, fantastic (also fantastical), outlandish, preposterous, ridiculous Near Antonyms applicable, functional, practicable, practical, reasonable, serviceable, usable (also useable), useful, working; likely, probable; acceptable, believable, conceivable, credible, plausible Antonyms achievable, attainable, doable, feasible, possible, realizable, resolvable, soluble, workable