Question

read the source of the allusion.
in greek mythology, sisyphus is punished by the gods with the task of eternally rolling a boulder up a hill just to watch it roll down again.
what is the meaning of the allusion in the sentence below?
in the mornings, working alone in the cold, i sometimes imagined myself to be trapped in a sisyphean nightmare.
unnatural
interminable

Explanation:

In Greek mythology, Sisyphus' task is eternal (he rolls the boulder up, it rolls down, and he repeats forever). The allusion in the sentence uses "Sisyphean" to imply a never - ending (interminable) situation, like the repetitive and unending nature of Sisyphus' punishment. "Unnatural" has no connection to the myth's key element of eternal repetition.

Answer:

interminable