The answer would be an Oxymoron.
Answer:
Here it means that when there is confusion and no hope. When there are purple jar of nights that is coming of night or darkness in your life or complete unsurety and you fall into it unaware of what is going to happen because you have no idea as to what is the solution of the problem.
Explanation:
These lines have been taken from the poem "Patience" by Amy Lowell.
Here, Hamlet is using a metaphor. Metaphors compare two things, yet differ from similes in that they don't use "like" or "as." He is comparing Denmark to a prison, meaning that he feels that the city is confining and bleak.
Im very sure its the nameless grace