be under par
To be below average; to be not as good as desired, required, or expected. This essay you turned in on Friday is really under par, Stevens. Has something been distracting you from your studies recently? Our food was rather uninteresting, and the service was really under par. I honestly don't understand why this restaurant is so popular! I'm a bit under par this morning, boss. I don't think I can make it in to work today!