insoluble
adjective uk/ɪnˈsɒl.jə.bəl/ us/ɪnˈsɑːl.jə.bəl/
(PROBLEM) (US also insolvable)(问题)无法解决的 (of a problem) so difficult that it is impossible to solve
Traffic congestion in large cities seems to be an insoluble problem. 大城市的交通堵塞问题似乎无法解决。
(SUBSTANCE) (物质)不能溶解的(of a substance) impossible to dissolve
These minerals are all insoluble in water. 这些矿物质都不溶于水。
Related word: insolubility