Flag is a little boring (8)
I believe the answer is:
tiresome
'boring' is the definition.
('tiresome' can be a synonym of 'boring')
'flag is a little' is the wordplay.
'flag' becomes 'tire' (I've seen this in other clues).
'is a little' becomes 'some' (I've seen this before).
'tire'+'some'='TIRESOME'
(Other definitions for tiresome that I've seen before include "Annoying, makes you fed up" , "Tedious, dull" , "Is remote, being boring" , "Wearying" , "wearing" .)