Tag line attached to murdered man (5)
I believe the answer is:
label
'tag' is the definition.
(synonyms)
'line attached to murdered man' is the wordplay.
'line' becomes 'l' (used when specifying particular lines from a poem).
'attached to' means one lot of letters go next to another.
'murdered man' becomes 'abel' (I have seen 'Third Man' mean 'abel' so perhaps 'man' could also mean 'abel'. I am not sure about the 'murdered' bit.).
'l'+'abel'='LABEL'
Can you help me to learn more?
(Other definitions for label that I've seen before include "Means of identifying" , "Identity tag" , "attachment to the Christmas parcel" , "Tag or designation" , "Name-tag" .)