The scientist spearheaded this groundbreaking research project.

spearheaded 是动词 spearhead 的过去式形式。spearhead 由名词 spear（长矛）和 head（头部）组成，字面意思是"长矛的尖端"，引申为"带头、领导"的意思，指像长矛尖端一样冲在最前面引领方向。