1. To engage in a sword duel against another person. I was a very skilled swordsman in my youth—I measured swords many times and lived to tell the tale.
2. To fight someone or something. Can you two stop measuring swords against each other? I'm sick of having to break up fights between you! I don't think you'll win if you try to measure swords with the big pharmaceutical company.
3. To get a sense of one's abilities in a particular area. After measuring swords with him this morning, I'm confident that I can beat him in the race—I know he's not as fast as I am!