Despite being outnumbered, the defenders resisted valiantly.

resisted 是动词 resist 的过去式，resist 由前缀 re-（表示"反对"）和词根 sist（来自拉丁语 sistere，意为"站立"）组成，字面意思是"站在对立面"，引申为"抵抗、反抗"的意思。