Action works both ways (4)
I believe the answer is:
deed
I believe this is a triple definition!
'action' is the first definition.
(deed is a kind of action)
'works' is the second definition.
(thesaurus)
'both ways' is the third definition.
(Other definitions for deed that I've seen before include "Act - exploit - legal document" , "Heroic exploit" , "What's done" , "A conscious action" , "documentary evidence" .)