Boring British country (5)
I believe the answer is:
bland
'boring' is the definition.
(I've seen this before)
'british country' is the wordplay.
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'country' becomes 'land' (synonyms).
'b'+'land'='BLAND'
(Other definitions for bland that I've seen before include "Without flavour" , "Insipid - uninteresting" , "Unruffled but unstimulating" , "Dull - tasteless" , "Flavourless" .)