Mindlessly repeat standard nonsense (6)
I believe the answer is:
parrot
'mindlessly repeat' is the definition.
(to parrot something is to repeat it)
'standard nonsense' is the wordplay.
'standard' becomes 'par' (standard of play in golf).
'nonsense' becomes 'rot' (rot can mean nonsense or rubbish).
'par'+'rot'='PARROT'
(Other definitions for parrot that I've seen before include "birdie" , "Unintelligent imitator" , "Amazon" , "Repeat automatically" , "Bird (that repeats)" .)