Middleman may get an order (5)
I believe the answer is:
agent
'middleman' is the definition.
(I've seen this before)
'get an order' is the wordplay.
'order' is an anagram indicator.
'get'+'an'='getan'
'getan' with letters rearranged gives 'AGENT'.
'may' acts as a link.
(Other definitions for agent that I've seen before include "Author" , "envoy" , "Bond, e.g." , "Spy - broker" , "One employed to incite others to commit illegal acts" .)