死結

tight knot / intractable problem

to die / impassable / uncrossable / inflexible / rigid / extremely / damned

(of a plant) to produce (fruit or seeds) / Taiwan pr. [jie2]

knot / sturdy / bond / to tie / to bind / to check out (of a hotel)

enigmatic knot hard to untie (idiom); thorny problem / intractable difficulty