Trust Football Association uncovered City hooligan's leader (5)
I believe the answer is:
faith
'trust' is the definition.
(I've seen this before)
'football association uncovered city hooligan's leader' is the wordplay.
'football association' becomes 'fa' (abbreviation).
'uncovered' says to take the centre.
'leader' says to take the initial letters.
The central letters of 'city' are 'it'.
The first letter of 'hooligans' is 'h'.
'fa'+'it'+'h'='FAITH'
(Other definitions for faith that I've seen before include "'..... will move mountains'" , "Unshakeable belief" , "Total trust" , "Strong belief in a supernatural power" , "religion" .)