Hippies' slogan (6,5)
I believe the answer is:
flower power
'hippies' slogan' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for flower power that I've seen before include "Sixties' peace and love movement" , "hippy cult" , "1960s hippies' movement" , "Hippy movement" .)