(1950s slang) A teenager who imitated the beatniks.
(1960s slang; still widely used in reference to that era) One who chooses not to conform to prevailing social norms: especially one who subscribes to values or actions such as acceptance or self-practice of recreational drug use, liberal or radical sexual mores, advocacy of communal living, strong pacifism or anti-war sentiment, etc.
(modern slang) A person who keeps an unkempt or sloppy appearance and wearing unusually long hair (for males), and because of it, often stereotyped as a deadbeat.
Someone who dresses in a hippie style.
One who is hip.