(of a problem, mystery, etc. 问题、谜团等 that cannot be solved or explained 无法解决的；不能解释的 The problem seemed insoluble. 问题似乎难以解决。
Oxford Collocations Dictionaryverbs- be
- seem
- remain
- …
- almost
- apparently
- seemingly
- …
- insoluble (in something)
(of a substance 物质 that does not dissolve in a liquid 不能溶解的；不溶的 These chemicals are practically insoluble in water. 这些化学物质几乎不溶于水。
Oxford Collocations Dictionaryverbs- be
- highly
- relatively
- almost
- …
- in
opposite soluble
Word Originlate Middle English: from Old French, or from Latin insolubilis, from in- ‘not’ + solubilis, from solvere ‘loosen, unfasten’.