cana
What does cana mean?
The police, the cops (collectively 'la cana'), or a single policeman. The source is debated; the Academia Portena del Lunfardo notes possible links to French argot 'canne' or to 'cana' (gray hair/old guard), without fixing one.
Origin
Lunfardo from the early-1900s Buenos Aires underworld and recorded by the Academia Portena del Lunfardo; as a piece of thieves' cant its etymology is genuinely uncertain, with French 'canne' and the 'gray-haired old guard' image both proposed.