Instrument fellow going to party left at home (8)
I believe the answer is:
mandolin
'instrument' is the definition.
(mandolin is a kind of instrument)
'fellow going to party left at home' is the wordplay.
'fellow' becomes 'man' (I've seen this before).
'going to' is a charade indicator (letters next to each other).
'party left at home' becomes 'dolin' (I can't justify this - if you can you should give a lot more credence to this answer).
'man'+'dolin'='MANDOLIN'
Can you help me to learn more?
(Other definitions for mandolin that I've seen before include "Lute-like instrument" , "Plucked instrument" , "'Captain Corelli's - - '" , "It takes some pluck to use this" , "it has strings attached" .)