Dull, bland (5)
I believe the answer is:
vapid
This clue is a double definition.
'dull' is the first definition.
(similar in meaning)
'bland' is the second definition.
(I know that bland can be written as vapid)
(Other definitions for vapid that I've seen before include "Boring or lifeless" , "no interest" , "Insipid, empty" , "Dull and boring" , "Lacking flavour" .)