Tedious case of dandy pinching bottom (6)
I believe the answer is:
dreary
'tedious' is the definition.
('dreary' can be a synonym of 'tedious')
'case of dandy pinching bottom' is the wordplay.
'case of' says to hollow out the word (remove centre letters) (outsides of).
'pinching' indicates putting letters inside (taking inside).
'bottom' becomes 'rear' ('rear' can be a synonym of 'bottom'**).
'dandy' with its centre removed is 'dy'.
'dy' placed around 'rear' is 'DREARY'.
(Other definitions for dreary that I've seen before include "Dull and depressing" , "Dismal, depressing" , "Bleak, depressing" , "routine" , "Gloomy and dismal" .)