First three from Musaeus about died, stick around for one to hurl abuse (10)
I believe the answer is:
mudslinger
'first three from musaeus' is the definition.
I can't tell whether this defines the answer.
'about died stick around for one to hurl abuse' is the wordplay.
'about' indicates putting letters inside.
'died' becomes 'd'.
'stick around' becomes 'linger'.
'for' says to put letters next to each other (I've seen this in other clues).
'one to hurl abuse' becomes 'mus' (I can't justify this - if you can you should give a lot more credence to this answer).
'linger' after 'mus' is 'muslinger'.
'd' inserted into 'muslinger' is 'MUDSLINGER'.
Can you help me to learn more?
(Other definitions for mudslinger that I've seen before include "Scandalmonger" , "Person trying to damage another's reputation" , "knocker" , "One making accusations" , "Slanderer" .)