Fuzz

The word came to mean the police  in American in 1929, when it was used as underworld slang and it gained popularity in the 1930s.   The Random House Historical Dictionary of American Slang marked the word as being  of unknown origin in its 1929 edition.  Two years later in 1931, it was recorded in Tramp and Underground Slang as meaning: “a detective, prison guard or turnkey.”

The explanation for hanging the term fuzz on the police is that when the police arrived at the scene of a crime, there was always a fuss.  And so, when a gang of small-time drug or liquor dealers and runners were  about to be raided by the police, they would refer to this as a fuss which eventually became fuzz.  The word fuzz stuck as slang for law enforcement officers.

The term surfaced in Britain in the 1960s and was used in both the UK and the US during the hippie era of the 60s.