Was untruthful about song (4)
I believe the answer is:
lied
This clue is a double definition.
'was untruthful' is the first definition.
(I've seen this before)
'song' is the second definition.
(type of German song)
'about' is the link.
(Other definitions for lied that I've seen before include "Did not speak the truth" , "Told untruths; song" , "gave a false impression" , "conveyed a false impression" , "Told fibs - German song" .)