expeditionary

1. not comparableOf or pertaining to an expedition.
2. not comparablegovernmentIntended for military operations abroad.

   an expeditionary force

plural expeditionaries

1. in pluralOne who goes on expeditions, especially one who is a member of an expeditionary military force.

   [...] turned out in its best attire to receive the Brazilian expeditionaries and the group of soldiers representing the gallant U.S. 10th Mountain Division.

   1966, João Baptista Mascarenhas de Moraes, The Brazilian Expeditionary Force by Its Commander

   1 more example

   He who had been left for dead, rose again in three days to become the leader of the expeditionaries and, in a very real way (albeit not exclusively), [...]. Antonio “ Tintin” Vizintin was brave and strong, qualities that made him a good expeditionary.

   2013, Matt J. Rossano, Mortal Rituals: What the Story of the Andes Survivors Tells Us About Human Evolution, Columbia University Press, →ISBN, page 81