Draw in though usually drawn up (8)
I believe the answer is:
contract
'draw in' is the definition.
(thesaurus)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for contract that I've seen before include "Promise" , "Document setting out terms of agreement" , "Agree - get smaller" , "bargain" , "Binding agreement between two or more" .)