concursator

concursātor, ōris, m. [concurso],

one who runs hither and thither; in milit. lang., a skirmisher (opp. statarius; rare, perh. only in Livy): concursator et vagus pedes, Liv. 31, 35, 6: levis et concursator hostis, id. 27, 18, 14.