Green’s Dictionary of Slang

hipidity n.

[hippie n.2 (3)]

(US campus) a usu. young person, preaching a philosophy of ‘love and peace’, backed by a wide spectrum of drug use, esp. cannabis and hallucinogens.

[US]G. Underwood ‘Razorback Sl.’ in AS L:1/2 61: hipidityn Hippie.