Boring, commonplace (7)
I believe the answer is:
I believe this clue is a double definition.
'boring' is the first definition.
(I've seen this in another clue)
'commonplace' is the second definition.
(I know that commonplace can be written as humdrum)
(Other definitions for humdrum that I've seen before include "without incident" , "Run-of-the-mill" , "Everyday, boring" , "Far from exciting" , "Boringly monotonous" .)