Defenceless as Venus de Milo? (7)
I believe the answer is:
unarmed
'defenceless' is the definition.
(not carrying a weapon)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for unarmed that I've seen before include "Not carrying a weapon" , "Lacking weapons" , "Having no means of defence" , "Not able to fire" , "Defenceless" .)