glancing blow

1. A physical strike that only partially connects with someone or something, imparting only a small amount of force as a result. I tried to knock him out, but he moved at the last second and I could only deliver a glancing blow across his temple. Luckily, I was driving so slowly that I only gave the car in front of me a glancing blow when I slid in the snow. You're gonna have a nice cut, but you shouldn't need stitches. Thank goodness that projectile only gave you a glancing blow!

2. By extension, that which has only a small or partial impact on something. Activists will be quick to remind people that the $2 million court settlement is merely a glancing blow to the giant corporation. Thankfully, our town only suffered a glancing blow from the storm. The headmaster has to expel this student now. Any lesser punishment would just be a glancing blow.