in arms

in arms

1. In combat, at war.
   • 1920, Hilaire Belloc, Europe and the Faith:

     It is worthy of remark, especially on the part of those who realize that the sword fits the hand of the Church and that Catholicism is never more alive than when it is in arms, I say it is worthy of remark by these that Spain and Portugal through the very greatness of an experience still recent when the Reformation broke, lost the chance of combat.

• brother-in-arms
• comrade in arms
• sister-in-arms