What is another word for "irresolvable"?

Roget's Thesaurus (1911) lists these synonyms for "irresolvable": abstract, ace, alone, and, apart, atomic, azygous, beat, but, combine, compact, desolate, dine, disjoin, disjunction, dreary, else, first, fort, half, indiscerptible, individual, individuality, indivisible, insecable, inseverable, insular, isolate, isolated, isolation, itself, join, last, lone, lonely, lonesome, monospermous, none, number, odd.