Definitions
1.nounThe pointed head, or end, of a spear.
2.nounOne who leads or initiates an activity (such as an attack or a campaign).
3.nounThe leading military unit in an attack.
4.nounA player who initiates attacking moves.
5.verbTo drive or campaign ardently for, as an effort, project, etc."He spearheaded the entire project from day one."