Airmen rattled by a serviceman (6)
I believe the answer is:
marine
'a serviceman' is the definition.
(marine is a kind of serviceman)
'airmen rattled' is the wordplay.
'rattled' indicates anagramming the letters.
'airmen' with letters rearranged gives 'MARINE'.
'by' is the link.
(Other definitions for marine that I've seen before include "Soldier-sailor" , "Member of the forces" , "Soldier associated with a navy" , "Relating to shipping or naval matters" , "Sea-soldier" .)