Talk over lease over some property (7)
I believe the answer is:
chattel
'some property' is the definition.
(chattel is a kind of property)
'talk over lease over' is the wordplay.
'talk' becomes 'chat' (chat can mean to talk).
'over' means one lot of letters go next to another (in a down clue, some letters go over others).
'lease' becomes 'let' (synonyms).
'over' shows that the letters should be reversed in order.
'let' written backwards gives 'tel'.
'chat'+'tel'='CHATTEL'
(Other definitions for chattel that I've seen before include "Movable possession" , "something one owns" , "Personal possession" , "Piece of portable property" , "Item of non-freehold property" .)