Foolishly relied on taking to court when abandoned (8)
I believe the answer is:
derelict
'abandoned' is the definition.
('derelict' can be a synonym of 'abandoned')
'foolishly relied on taking to court' is the wordplay.
'foolishly' is an anagram indicator.
'on' says to put letters next to each other.
'taking to court' becomes 'ct' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'relied' is an anagram of 'dereli'.
'dereli'+'ct'='DERELICT'
'when' is the link.
Can you help me to learn more?
(Other definitions for derelict that I've seen before include "Abandoned and ruined" , "Deserted and neglected" , "Disused, in poor condition" , "Of building, deserted and left to fall into ruin" , "Tramp" .)