Two lines are padding inferior song (6)
I believe the answer is:
ballad
'song' is the definition.
(I know that ballad is a type of song)
'two lines are padding inferior' is the wordplay.
I cannot really understand how this works, but
'lines' could be 'll' (an abbreviation for line written twice) and 'll' is present in the answer.
'are' could be 'a' (short for 'are', historical unit of measurement) and 'a' is found in the answer.
'inferior' could be 'bad' (similar in meaning) and 'bad' is found in the remaining letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for ballad that I've seen before include "romance" , "A simple or old song" , "Form of verse" , "Folk song" , "Lay, narrative song" .)