Complaint he conveys when entertaining one (7)
I believe the answer is:
malaise
'complaint' is the definition.
(thesaurus)
'conveys when entertaining one' is the wordplay.
'conveys' becomes 'malis' (I can't justify this - if you can you should believe this answer much more).
'when' becomes 'e' (I've seen this in other clues).
'entertaining' is an insertion indicator (inviting in, as for dinner).
'one' becomes 'a' (a thing is one thing).
'malis'+'e'='malise'
'malise' enclosing 'a' is 'MALAISE'.
'he' acts as a link.
This may not be correct. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for malaise that I've seen before include "Feeling of illness or mental uneasiness" , "General feeling of unease or illness" , "sickness" , "General feeling of discomfort" , "Feeling of impending illness" .)