Shrink from engagement (8)
I believe the answer is:
contract
This clue is a double definition.
'shrink' is the first definition.
(I know that contract is a kind of shrink)
'engagement' is the second definition.
(thesaurus)
'from' is the link.
(Other definitions for contract that I've seen before include "bargain" , "Undertake" , "four spades, perhaps" , "Make smaller" , "Shrink in legal agreement?" .)