Line adopted by FIFA fixed court trouble (7)
I believe the answer is:
afflict
'trouble' is the definition.
('afflict' can be a synonym of 'trouble')
'line adopted by fifa fixed court' is the wordplay.
'line' becomes 'l'.
'adopted by' indicates putting letters inside (I've seen this in other clues).
'fixed' is an anagram indicator.
'court' becomes 'ct'.
'fifa' is an anagram of 'affi'.
'l' going into 'affi' is 'affli'.
'affli'+'ct'='AFFLICT'
(Other definitions for afflict that I've seen before include "Painfully affect" , "Cause suffering to" , "Ail" , "Trouble; affect" , "Distress mentally or physically" .)