Prick is a vulgar word for penis as well as a pejorative term used to refer to a despicable or contemptible individual, usually male. It is generally considered offensive, though in the past it has been used as a term of endearment. Its history as a euphemism for penis goes back to the 1500s and has been used in wordplay by Shakespeare and other writers who have combined the vulgarism with the standard meaning of the noun, which means the act of piercing or puncturing. Most linguists believe it has only been used as a direct insult since 1929.
Modern dictionaries agree on prick as a euphemism for penis. But they offer some slight variations in the use of prick as an insult. The Concise New Partridge Dictionary of Slang says a prick is: “a despicable man, a fool, used as a general term of offense or contempt. Often as an abusive form of address, always of a male or an inanimate object. .” Similarly The Oxford Dictionary of English says “a stupid or contemptible man.” Merriam Webster offers, “a spiteful or contemptible man often having some authority”
Peter Silverton notes that the way a person calls another person a prick, which can range from disdain to anger, will help to define its meaning: “Said lightly, it's a jerk or a bumbler. Said with a harsher punchier intonation it can mean something far nastier. Say “Don't be such a prick, vs. “You prick!”
In modern times, says Tony Thorne, “in polite company it is the least acceptable of the many terms for the male member (cock, tool, etc.) , it is nevertheless commonly used, together with dick, by women in preference to those alternatives.”
The word comes from the Middle English prikke, which originates in the Old English, prica “point, puncture, particle, small portion of space or time.” The meaning of prick as a 'pointed weapon' or 'dagger' is first noted in the 1550s. Prick as a verb for sexual intercourse can be seen as early as the 14th century, in Geoffrey Chaucer's Canturbury Tales. The Oxford English Dictionary records the first use of the word prick as penis in 1592, although it was probably used in the spoken language for some time before. It was “probably coined with the image of a thorn in mind from the shape and image of penetration evoked.", says Thorne. The earliest use of the noun prick as penis is observed in the works of Shakespeare, who uses it playfully several times as a double entendre with the non-sexual meaning of prick, i.e., “the act of puncturing” as in the following examples: