Boredom, ennui (6)
I believe the answer is:
tedium
This clue is a double definition.
'boredom' is the first definition.
(I know that boredom can be written as tedium)
'ennui' is the second definition.
(I know that ennui can be written as tedium)
(Other definitions for tedium that I've seen before include "Banality" , "Dullness, monotony" , "Routine" , "boring" , "'Boredom, ennui (6)'" .)