Feeling of weariness or boredom (5)
I believe the answer is:
ennui
I believe this is a double definition.
'feeling of weariness' is the first definition.
(I've seen this before)
'boredom' is the second definition.
(I know that boredom is a class)
(Other definitions for ennui that I've seen before include "Feeling of disaffection" , "Result of boredom" , "tiredness" , "doldrums" , "having nothing to do" .)