Hammer or sickle (4)
I believe the answer is:
tool
I believe this clue is a double definition.
'hammer' is the first definition.
(I've seen this in another clue)
'sickle' is the second definition.
(thesaurus)
(Other definitions for tool that I've seen before include "Implement - agency" , "Instrument, implement" , "Practical implement" , "Cat's-paw; impress design on" , "For example, saw" .)