dick

The word 'dick' originated as a medieval rhyming slang nickname for 'Rick', itself a short form of 'Richard'. By the 16th century, it had become a generic term for any fellow or man, much like 'jack' or 'tom'. In the 19th century, this generic usage began to be applied euphemistically to refer to the male body, likely due to the common practice of using common male names as slang for the penis. This euphemistic use solidified in the 20th century, eventually becoming the primary vulgar meaning, while the older, neutral sense of "a guy" became largely obsolete.

This word is a simplex. It is a given name of Germanic origin (from Theodoric, meaning "people-ruler") that became a common English nickname and later entered slang.