Boring, being outside playing (7)
I believe the answer is:
tedious
'boring' is the definition.
('tedious' can be a synonym of 'boring')
'outside playing' is the wordplay.
'playing' indicates an anagram.
'outside' anagrammed gives 'TEDIOUS'.
'being' is the link.
(Other definitions for tedious that I've seen before include "Dull as ditchwater" , "drab" , "Tiresome, boring" , "not worth listening to?" , "Banal" .)