Last in catalogue a great composer (5)
I believe the answer is:
liszt
'a great composer' is the definition.
'liszt' can be an answer for 'composer' (Franz Liszt). I am unsure of the 'a great' bit.
'last in catalogue' is the wordplay.
'last' becomes 'z' (I can't justify this - if you can you should believe this answer much more).
'in' means one lot of letters goes inside another.
'catalogue' becomes 'list' (a catalogue is a list of items).
'z' inserted inside 'list' is 'LISZT'.
Can you help me to learn more?
(Other definitions for liszt that I've seen before include "Franz -, Hung. pianist" , "classical composer" , "Brahms and - is rhyming slang for drunk" , "Famous composer" , "music writer" .)