Boy gets German tune (4)
I believe the answer is:
song
'tune' is the definition.
(I've seen this before)
'boy gets german' is the wordplay.
'boy' becomes 'son' (synonyms).
'gets' says to put letters next to each other.
'german' becomes 'g' (abbreviation).
'son'+'g'='SONG'
(Other definitions for song that I've seen before include "Vocal item" , "Musical composition with words" , "Carol, for example" , "Melody (which is cheap to go for)" , "Musical number" .)