Fools capture the first estate (6)
I believe the answer is:
assets
'estate' is the definition.
(I've seen this in another clue)
'fools capture the' is the wordplay.
'fools' becomes 'asses' (ass can mean a foolish person).
'capture' means one lot of letters goes inside another.
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'asses' enclosing 't' is 'ASSETS'.
'first' is the link.
(Other definitions for assets that I've seen before include "Total value of possessions" , "Personal wealth" , "Useful skills" , "Possessions and resources" , "Valuables, things worth having" .)