Inclination to write repetitive song (8)
I believe the answer is:
penchant
'inclination' is the definition.
(I've seen this before)
'write repetitive song' is the wordplay.
'write' becomes 'pen' ('pen' can be a synonym of 'write').
'repetitive song' becomes 'chant' (I've seen this before).
'pen'+'chant'='PENCHANT'
'to' acts as a link.
(Other definitions for penchant that I've seen before include "Partiality" , "'Predilection, a strong liking (8)'" , "Leaning towards or liking for" , "Inclination; taste" , "Strong liking, inclination" .)