Diu (Chinese: 屌, Hong Kong cangjie: [門+小], jyutping: diu2) is a common profanity in Cantonese. It can be regarded as the Cantonese equivalent of the English fuck.
Diu is a word in the Cantonese language. It appears frequently in the text of the classic novel Water Margin, and is written as 鳥 (meaning "bird", pronounced niǎo in Mandarin and niu5 in Cantonese when used in this usual sense). It is used as an emphatic adjective with a function similar to the English "fucking", "bloody" or "god damned". For example,
Chinese: 武松指著蔣門神，說道：「休言你這廝'''鳥'''蠢漢！景陽岡上那隻大蟲，也只三拳兩腳，我兀自打死了！量你這個直得甚麼！快交割還他！但遲了些個，再是一頓，便一發結果了你廝！」Water Margin, Chp. 29Diu means primarily the penis. It is written as 屌 when used in this sense, but usually as 鳥 when used as an emphatic adjective. For example,
Chinese: 木寸、馬户、尸巾，你道我是個「村驢'''屌'''」？Romance of the Western Chamber (Chinese: 西廂記), Act 5, Scene 3 (Chinese: 第五本第三折)Chinese: 屌 has its female equivalent 屄 (pronounced bī in Mandarin and hai1 in Cantonese) in the traditional Chinese written language. In the Yuan Dynasty operas, the word, meaning penis, is sometimes written as 頹. For example,
Chinese: 我見了些覓前程俏女娘，見了些鐵心腸男子漢，便一生里孤眠，我也直甚'''頹'''！Jiu Fengchen (Chinese: 救風塵), Act 1 (Chinese: 第一折)
The written form Chinese: [{{lang|zh|門}}+{{lang|zh|小}}] is mainly seen in Hong Kong, although the younger generation use Chinese: 屌 for example on graffiti. In Cantonese, it is used as a transitive verb meaning to copulate. In a manner similar to the English word fuck, it is also used to express dismay, disgrace, disapproval and so on. For example, someone may shout "diu nei!" ("fuck you!" or "fuck off!") at somebody when he or she finds that other person annoying.
"Diu Nei Lo Mo!" (Chinese: 屌你老母 or 你老母, "fuck your mother")[1] is a highly offensive profanity in Cantonese when directed against a specific person instead of used as a general exclamation. In contrast to the English phrase "fuck your mother", which indicates that the person being attacked commits sexual acts with his own mother, the Cantonese expression has the implied meaning of "I fuck your mother".
The form Chinese: is absent in the Big-5 character set on computers. The Government of Hong Kong has extended Unicode and the Big-5 character set with the Hong Kong Supplementary Character Set (HKSCS), which includes Chinese characters only used in Cantonese, including the Five Great Profanities. The government explained that the reason for these characters being included is to allow for the Hong Kong Police to record criminal suspects' statements. Consequently, these characters are now also in Unicode.
In Hong Kong Cantonese, yiu (Chinese: [[Wikt:妖|妖]]), tiu (Chinese: [[Wikt:挑|挑]]), siu (Chinese: [[Wikt:小|小]]), chiu (Chinese: [[Wikt:超|超]]), biu (Chinese: [[Wikt:表|表]]), and hiu (Chinese: [[Wikt:曉|曉]]) are all minced oaths for diu, as they all rhyme with "iu".