The definition of a hipster is opaque and unclear to anyone who is not a hipster. Hipsters are basically young people, usually with middle class upbringing, who follow the latest trends. A hipster is basically a person who is hip.
Hipsters pick up a trend even before it has gotten popular, and by the time it does get popular, hipsters have often moved onto a newer trend. Hence, the running joke, “…because the hipster did it before it was cool.” This is basically a reference to the fact that they accept a trend even before it is cool or popular.
Hipsters are generally associated with indie and alternative music, a varied non-mainstream fashion sensibility, such as vintage and thrift store-bought clothes, as well as generally progressive political views, organic and artisanal foods, and alternative lifestyles. They are often considered to be contemporary bohemians.
The hipster culture arose in the 1990s and gained popularity and prominence in the 2010s. There was another hipster movement in the 1940s in the United States but it was somewhat different that the hipster culture of today. Nowadays, hipsters are often ridiculed and the word ‘hipster’ is often used as a negative word to describe someone who is pretentious, overly trendy or effete.