advance guard, airhead, ancestor, announcer, antecedent, avant-garde, battle line, beachhead, bellwether, bridgehead, buccinator, bushwhacker, explorer, farthest outpost, first line, forebear, forefront, foregoer, forerunner, front, front line, front rank, front runner, frontiersman, fugleman, groundbreaker, guide, harbinger, herald, innovator, lead runner, leader, line, messenger, outguard, outpost, pathfinder, pioneer, point, precedent, precursor, predecessor, railhead, scout, spearhead, stormy petrel, trailblazer, trailbreaker, van, vanguard, vaunt-courier, voortrekker