Insoluble

прилагательное 1) нерастворимый Например: insoluble matter — нерастворимое вещество insoluble residue — нерастворимый остаток 2) неразрешимый 3) [устаревшее] нерушимый

Большой англо-русский словарь

Insoluble

adjective Etymology: Middle English insolible, from Latin insolubilis, from in- + solvere to free, dissolve — more at solve not soluble: as a. archaic indissoluble b. having or admitting of no solution or explanation Example: an insoluble problem c. incapable of being dissolved in a liquid and especially water; also soluble only with difficulty or to a slight degree • insolubility nouninsoluble nouninsolubleness nouninsolubly adverb

Энциклопедический словарь Мерриама-Вебстера