Fellow having trouble on Yorkshire river is a loser (7)
I believe the answer is:
failure
'a loser' is the definition.
('failure' can be a synonym of 'loser')
'fellow having trouble on yorkshire river' is the wordplay.
'fellow' becomes 'f' (abbreviation - of a society etc.).
'having' means one lot of letters go next to another.
'trouble' becomes 'ail' ('ail' can be a synonym of 'trouble'**).
'on' is a charade indicator (letters next to each other).
'yorkshire river' becomes 'ure' (I've seen this in other clues).
'f'+'ail'+'ure'='FAILURE'
'is' is the link.
(Other definitions for failure that I've seen before include "Collapse; disaster" , "Defeat" , "Lack of success, or he who lacks it" , "[OPPOSITE OF] success" , "Fiasco" .)