An exploit is a heroic act or notable deed. The King Arthur legends are full of stories of the exploits of the Knights of the Round Table, including Sir Lancelot and King Arthur himself.
This noun is from Middle English expleit, "outcome," from Latin explicitus, "unfolded, set forth." The verb exploit means to use someone or something, usually selfishly or for profit. Workers who are tired of being exploited by factory owners form unions that allow them to stand together as a powerful force.