Formal/General:
* Un hippie (literally "a hippie") is the most common and direct translation.
Informal/Slang:
* Un baba cool is a more informal and playful term, meaning something like "a cool dude/chick". This is more about the relaxed and free-spirited attitude of hippies.
* Un flower power (literally "flower power") is a slang term referencing the iconic symbol of the hippie movement.
* Un enfant des fleurs (literally "a child of flowers") is another slang term that emphasizes the connection to nature and peace.
Specific contexts:
* If you are talking about the hippie movement in the 1960s, you can also use un enfant des années 60 (literally "a child of the 1960s").
* For a more specific description of a hippie's appearance, you could use une personne avec des vêtements psychédéliques (a person with psychedelic clothes).
Ultimately, the best French translation of "hippie" will depend on the context and the intended meaning.