With the agreements cheats, seizing a piece of land (9)
I believe the answer is:
contracts
'with the agreements cheats seizing a piece of land' is the definition.
I can't tell whether this definition defines the answer.
'cheats seizing a piece of land' is the wordplay.
'cheats' becomes 'cons' (con is a kind of cheat).
'seizing' means one lot of letters goes inside another (inserted letters are seized).
'a piece of land' becomes 'tract' (tract can mean an area of land).
'cons' enclosing 'tract' is 'CONTRACTS'.
Can you help me to learn more?
(Another definition for contracts that I've seen is " Legal agreements".)