indissoluble (adj.)youdaoicibaDictYouDict[indissoluble 词源字典]
mid-15c. (implied in indissolubly), from Latin indissolubilis "that cannot be dissolved," from in- "not, opposite of" (see in- (1)) + dissolubilis, from dis- + solubilis (see soluble).[indissoluble etymology, indissoluble origin, 英语词源]