Human being ethical about trade primarily (6)
I believe the answer is:
mortal
'human being' is the definition.
(thesaurus)
'ethical about trade primarily' is the wordplay.
'ethical' becomes 'moral' ('moral' can be a synonym of 'ethical').
'about' indicates putting letters inside.
'primarily' says to take the initial letters.
The initial letter of 'trade' is 't'.
'moral' placed around 't' is 'MORTAL'.
(Other definitions for mortal that I've seen before include "Sound a wound is deadly" , "Causing death" , "liable to die" , "Human - transitory" , "Destined to die" .)