unsolvable

US /ʌnˈsɑːl.və.bəl/
UK /ʌnˈsɑːl.və.bəl/
1.

không thể giải quyết được

If a problem, difficulty, or mystery is unsolvable, it is not possible to find a solution to it or the cause of it:

:
Without further funds, this is an almost unsolvable problem.