Synonyms and related words :
abnormal, absurd, ambiguous, ambivalent, anomalous, antinomic, baffling, barred, bewildering, closed-out, conflicting, confusing, contradictory, contrary to reason, disproportionate, enigmatic, equivocal, excluded, hopeless, illogical, impossible, improbable, incoherent, incommensurable, incommensurate, incompatible, incomprehensible, inconceivable, incongruous, inconsequent, inconsistent, inconsonant, ironic, irreconcilable, logically impossible, mysterious, not possible, out of proportion, oxymoronic, perplexing, preposterous, problematic, prohibited, puzzling, ridiculous, ruled-out, self-contradictory, unimaginable, unthinkable