Boring sport, one followed by a few? (9)
I believe the answer is:
wearisome
'boring' is the definition.
('wearisome' can be a synonym of 'boring')
'sport one followed by a few' is the wordplay.
'sport' becomes 'wear' (I've seen this before).
'one' becomes 'i' (Roman numeral).
'followed by' says to put letters next to each other.
'a few' becomes 'some' (I've seen this before).
'wear'+'i'+'some'='WEARISOME'
(Other definitions for wearisome that I've seen before include "pestilential" , "Boring" , "Tedious, tiring" , "Trying" , "Vexatious" .)