Orion hit a rabbit once; but though sore wounded it got to the bury, and, struggling in, the arrow caught the side of the hole and was drawn out.[…]. Ikey the blacksmith had forged us a spearhead after a sketch from a picture of a Greek warrior; and a rake-handle served as a shaft.
One who leads or initiates an activity (such as an attack or a campaign).
1964 September, G. Freeman Allen, “Interim report on the East Coast Route express service”, in Modern Railways, pages 158–159:
Spearheads of the NER bargain fares attack this year have been the introduction of weekend fares at a 7s 6d in the £ discount on ordinary rates between principal stations throughout the Region—[...].
England played at a tempo in attack that was too much for Bulgaria, with width provided at various times by Walcott, Young and Stewart Downing and Rooney acting as the potent spearhead.