Hip, like cool, does not refer to one specific quality. What is considered hip is continuously changing. Being hip is also about being informed about the latest ideas, styles, and developments.
Origin of term
The term hip is recorded in African American Vernacular English in the early 1900s. In the 1930s and 1940s, it had become a common slang term, particularly in the African-American-dominated jazz scene. The exact origin of hip is unknown. There are many different explanations for the etymology of hip, but they remain unproven. Research and speculation by both amateur and professional etymologists suggest that "hip" is derived from an earlier form, hep, but that is disputed. Many etymologists believe that the terms hip, hep, and hepcat derive from the west African Wolof language word hepicat, which means "one who has his eyes open". Some etymologists reject this, however, tracing the origin of this putative etymology to David Dalby, a scholar of African languages who tentatively suggested the idea in the 1960s, and some have even adopted the denigration "to cry Wolof" as a general dismissal or belittlement of etymologies they believe to be based on "superficial similarities" rather than documented attribution. Alternative theories trace the word's origins to those who used opium recreationally. Because opium smokers commonly consumed the drug lying on their sides, or on the hip, the term became a coded reference to the practice; and because opium smoking was a practice of socially influential trend-setting individuals, the cachet it enjoyed led to the circulation of the term hip by way of a kind of synecdoche. This etymology is, however, rejected by Sheidlower. Slang dictionaries of past centuries give a term hip or hyp meaning melancholy or bored, shortened from the wordhypochondriac. However, this usage, more prevalent around 1800, was virtually extinct by 1900.
Development
The word hip in the sense of "aware, in the know" is first attested in a 1902 cartoon by Tad Dorgan, and first appeared in print in a 1904 novel by George Vere Hobart, Jim Hickey, A Story of the One-Night Stands, where an African-American character uses the slang phrase "Are you hip?" Early currency of the term is further documented in the 1914 novel The Auction Block by Rex Beach: After the Second World War, the term moved into general parlance. The English humorist P.G. Wodehouse has his aristocratic narrator, Bertie Wooster, use the term "get hep" in his 1946 novel Joy in the Morning. Jack Kerouac described his mid-century contemporaries as "the new American generation known as the 'Hip' "; In 1947, Harry "The Hipster" Gibson wrote the song "It Ain't Hep" about the switch from hep to hip:
Hey you know there's a lot of talk going around about this hip and hep jive. Lots of people are going around saying "hip." Lots of squares are coming out with "hep." Well the hipster is here to inform you what the jive is all about.