supercargo
noun
su·per·car·go ˌsü-pər-ˈkär-(ˌ)gō 
ˈsü-pər-ˌkär-
: an officer on a merchant ship in charge of the commercial concerns of the voyage
Word History
Etymology
Spanish sobrecargo, from sobre- over (from Latin super-) + cargo cargo
First Known Use
1667, in the meaning defined above