Policemen around the world have different nicknames. In the US, they are often called cops. The word "cop" is a shortened version of "copper", which originated in Britain. British police are also called bobbies. This word has an interesting origin. The first organized and professional police force in Britain was created in London in 1829 by a politician named Robert Peel. The name "Robert" is often shortened to "Bobby" or "Bob". That's why British police are often called bobbies, named after Robert Peel. The police are sometimes called "the fuzz". During the 1960s and 1970s, the police were called "pigs". This is a derogatory (insulting, offensive) word against the police. It is unclear how or when the words "the fuzz" or "pigs" originated as slang words for the police.
Anti-extradition bill protesters in Hong Kong now call the police "black cops" in Chinese. The expression "black cops" is not an exact translation of the Chinese expression. In Cantonese, it is "huk king", which means "black police". The word "black" in this case comes from the word "triad", which in Chinese is "black society". Anti-government protesters believe the police are in cahoots with the triads. That's why the protesters call the police black cops, which means triad cops. If you are in cahoots with people, it means you are secretly cooperating with them to do illegal things. I do not know if the police are really in cahoots with the triads to fight against the anti-extradition bill protests. But most Hong Kong people believe the police are in cahoots with the triads.
Before the anti-extradition bill protests, most people would respectfully call the police "sir". This is a tradition from the colonial days. I have many police friends because of my job as a journalist. Whenever I see them I call them "sir". In the US, it is common to call people "sir" to be polite. Even policemen would call ordinary people "sir" to be polite. The police in Hong Kong would never call ordinary people "sir", especially at this time when there is so much mistrust between the police and the public.
警察在世界各地有不同花名。在美國，他們常被稱作「cops」。「Cop」一字其實是「copper」的簡稱，後者源自英國。英國警察也會被喚作「bobbies」，這個字的來源就有趣了。英國第一支有組織及專業的警隊，是由一位名羅伯特．皮爾的政客在一八二九年創立。而他的名字羅伯特「Robert」常被簡稱為「Bobby」或「Bob」，因此英國警隊也常被喚作「bobbies」，正是以羅伯特．皮爾而得名。警隊有時也被喚作「the fuzz」。在一九六○和一九七○年代，警隊也被叫作「pigs」，這是對警隊的一個帶貶義（derogatory）的字。「The fuzz」或「pigs」是怎樣又或何時開始成為稱呼警隊的俚語，已不得而知。
香港反逃犯條例的示威者現在稱呼警察為「黑警」（black cops）。「Black cops」一詞其實並非確切的翻譯，廣東話說的「黑警」，意思是「black police」；在這裏，「黑」字是來源於「黑社會」。反政府示威者相信警察與三合會勾結（in cahoots），因此示威者便叫警察做「黑警」（black cops），意即黑社會警察。若你是「in cahoots with people」，即是說你與某些人勾結，合謀做非法的事。我不知道警方在打擊反逃犯條例示威期間，是否真的跟三合會勾結（in cahoots），但大部份香港人也相信警方真的有跟三合會勾結（in cahoots）。
Michael Chugani 褚簡寧