For preference, decrepit lion to be shot (12)
I believe the answer is:
predilection
'for preference' is the definition.
(synonyms)
'decrepit lion to be shot' is the wordplay.
'to be shot' is an anagram indicator.
'decrepit'+'lion'='decrepitlion'
'decrepitlion' is an anagram of 'PREDILECTION'.
(Other definitions for predilection that I've seen before include "Preference (for something)" , "taste" , "Special liking or preference" , "Penchant" , "Fondness" .)