insuperable

1 incapable of being defeated, overcome, or subdued the building project ran into insuperable financial difficulties and had to be scrapped Synonyms bulletproof, impregnable, indomitable, invincible, insurmountable, invulnerable, unbeatable, unconquerable, unstoppableRelated Words inviolable, unassailable, unbreachable, untouchable; armored, defended, guarded, protected, safe, safeguarded, secure, shielded; unbeaten, unbowed, unconquered, undefeated, unsubduedNear Antonyms exposed, imperiled (or imperilled), insecure, liable, open, susceptible, unguarded, unprotected, unsafe; defenseless, helpless, powerless, weakAntonyms superable, surmountable, vincible, vulnerable

2 incapable of being solved or accomplished insuperable problems have arisen which make it very unlikely that we will ever finish this project Synonyms hopeless, insoluble, insolvable, impossible, unattainable, undoable, unrealizable, unsolvableRelated 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, ridiculousNear Antonyms applicable, functional, practicable, practical, reasonable, serviceable, usable (also useable), useful, working; likely, probable; acceptable, believable, conceivable, credible, plausibleAntonyms achievable, attainable, doable, feasible, possible, realizable, resolvable, soluble, workable