Beatniks somewhat high starting to puff on empty pipes (7)
I believe the answer is:
hippies
'beatniks' is the definition.
'somewhat high starting to puff on empty pipes' is the wordplay.
'somewhat high' becomes 'hi' (I can't justify this - if you can you should believe this answer much more).
'starting to' indicates taking the first letters.
'on' is a charade indicator (letters next to each other).
'empty' says to hollow out the word (remove centre letters).
'pipes' with its centre removed is 'pies'.
The initial letter of 'puff' is 'p'.
'hi'+'p'+'pies'='HIPPIES'
(Another definition for hippies that I've seen is " Flower people".)