on ones deathbed (adjective) moribund: dying
Sinonime: baffling, enigmatic, incomprehensible, indecipherable, indescribable, inexplainable, inscrutable, insoluble, mysterious, mystifying, obscure, odd, peculiar, puzzling, strange, unaccountable, undefinable,
unexplainable, unfathomable, unintelligible, unsolvable
Antonime: comprehendible, explainable, explicable,
intelligible