Fellow dined inside, enthused hollowly, and came out (8)
I believe the answer is:
emanated
'came out' is the definition.
(I've seen this in another clue)
'fellow dined inside enthused' is the wordplay.
'fellow' becomes 'man' (fellow can mean a man).
'dined' becomes 'ate' (I've seen this in another clue).
'inside' is an insertion indicator.
'enthused' becomes 'ed' (I can't justify this - if you can you should give a lot more credence to this answer).
'man'+'ate'='manate'
'manate' put into 'ed' is 'EMANATED'.
'hollowly and' acts as a link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for emanated that I've seen before include "Flowed" , "Issued forth, as from a source" , "Issued or originated from a source" , "came forth" , "Emerged or originated" .)