Erroneous fines discovered by a court (7)
I believe the answer is:
inexact
'erroneous' is the definition.
(thesaurus)
'fines discovered by a court' is the wordplay.
'discovered' says to take the centre (dis-covered - outer letters removed).
'by' becomes 'x' (as in 'multiplied by').
'court' becomes 'ct' (abbreviation used in road names).
The centre of 'fines' is 'ine'.
'ine'+'x'+'a'+'ct'='INEXACT'
(Other definitions for inexact that I've seen before include "Not quite right" , "Not precise, ambiguous" , "not precisely correct" , "estimated?" , "Fuzzy, muddled" .)