Artist leaving the party gives a reason to sue (5)
I believe the answer is:
libel
'artist leaving' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
'party gives a reason to sue' is the wordplay.
I cannot really see how this works, but
'party' could be 'lib' (abbreviation for Liberal, uk political party) and 'lib' is found within the answer.
The remaining letters 'el' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'the' acts as a link.
Can you help me to learn more?
(Other definitions for libel that I've seen before include "Defamatory publication" , "false report" , "Calumnious writing" , "Written defamation" , "False and malicious publication to defame" .)