Silly person that would expect real profits initially! (5)
I believe the answer is:
twerp
'silly person' is the definition.
(twerp can mean a silly or annoying person)
'that would expect real profits initially' is the wordplay.
'initially' suggests taking the first letters.
The initial letters of 'that would expect real profits' is 'TWERP'.
(Other definitions for twerp that I've seen before include "Foolish fellow" , "Twit" , "Fool" , "Silly person" , "Contemptible person" .)