Flipping tedious - that's Shakespeare! (4)
I believe the answer is:
bard
'shakespeare' is the definition.
(I've seen this before)
'flipping tedious' is the wordplay.
'flipping' is a reversal indicator.
'tedious' becomes 'drab' (I've seen this before).
'drab' reversed gives 'BARD'.
'that's' is the link.
(Other definitions for bard that I've seen before include "Eisteddfod winner" , "Animal; cruel person" , "Traditional poet" , "Ancient poet" , "Celtic poet" .)