Come down with a fellow salesperson (4,5)
I believe the answer is:
land agent
'salesperson' is the definition.
The answer and definition can be both people as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'come down with a fellow' is the wordplay.
'come down' becomes 'land' (to land is to come down after flying).
'with' means one lot of letters go next to another.
'fellow' becomes 'gent' (synonyms).
'land'+'a'+'gent'='LAND-AGENT'
Can you help me to learn more?
(Other definitions for land agent that I've seen before include "Estate steward" , "Estate manager" , "Scots factor" .)