Italy's largest lake (5)
I believe the answer is:
garda
'italy's largest lake' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for garda that I've seen before include "Irish state police force" , "Irish police officer" , "Policeman of the Irish Republic" , "One of our police - what a drag" , "An Irish limb of the law" .)