Of course, in its modern noun sense, the term ‘jockey’ is used to describe a person who rides in horse races, especially professionally. However, ‘Jockey’ was originally the diminutive, or familiar, form of ‘Jock’, which, in the North of England and Scotland, is a nickname for John, dating back to the late medieval period. For example, John Howard, First Duke of Norfolk, who was killed on Bosworth Field in 1485, while fighting for King Richard III, was known colloquially as ‘Jockey of Norfolk’. Indeed, Howard was referenced as such by William Shakespeare in his chronical play ‘Richard III’, which was written circa 1592-1594.
Aside from its use as a proper name, ‘Jockey’ was also employed generically – in the sense of ‘Tom, Dick or Harry’ – as the name of an ordinary, or subordinate, man or boy. In this respect, the term was used specifically to describe an estafette, or mounted courier, which led to the current sense circa 1670.According to John Camden Hotten, author of ‘The Slang Dictionary’, ‘jockey’ is derived from the Gipsy language, specifically from the word ‘ chuckni’, meaning ‘whip’.
‘Jockey’ was also used, in a secondary sense, to describe horse traders and other individuals with a reputation for dishonesty and so came to mean a cheat, shark or trickster. Thus, in its verb sense, ‘jockey’ came to mean to manipulate, outwit ot trick, in an effort to gain an advantage, probably pecuniary. Naturally enough, term was also used to describe the behaviour of jockeys manoeuvring for position, to gain an advantage, during a horse race.