Palms off a song (5)
I believe the answer is:
psalm
'a song' is the definition.
(I've seen this before)
'palms off' is the wordplay.
'off' is an anagram indicator.
'palms' anagrammed gives 'PSALM'.
(Other definitions for psalm that I've seen before include "Old Testament hymn" , "OT hymn" , "Jewish hymn" , "A song which praises" , "Song - hymn - prayer" .)