On-winnan

According to the Old English Dictionary:

on-winnan

to attack, assail :-- Sum hǽðen mann þe him swýðost onwann áwédde ðǽrríhte, Hml. S. 22, 131. Þæt gé eówerne eard bewerian mid wǽpnum wið onwinnendne here, Ælfc. T. Grn. 11, 18: Hml. S. 25, 818. Hí weredon hí cénlíce wið þone onwinnendan here, 589: 719. Hé gefeaht wið heora onwinnendan he fought with their assailants, 687. Seó scolu cildisc ná gýt mid costungum onwunnen scola puerilis nondum temptationibus inpugnata, Angl. xiii. 387, 321. on-winnan