expression, ichidan verb
cross swords; engage in battle; fight
Idiomatic expression literally meaning 'to cross spears', used for engaging in combat or a heated confrontation. Often used in historical or literary contexts.
両軍は平原で矛を交えた。
The two armies crossed spears on the plain.
彼らは激論の末、ついに矛を交えることになった。
After a heated argument, they finally came to blows.