It's in the red oak side of the family since it has pointed leaves. The funny leaf pattern is caused by stress. The leaves are fighting to flush out as much as possible on the good side, to keep the tree alive, but the other side may have bark damage or roots have choked it off and now it can't support growth so is dying/dead. With TLC it may recover, you could wait and see, but consider just replacing it.
From the photo, my guesses are 1) it was hit by the lawnmower deck or string trimmer too many times, and had lost the life supporting bark layer of cambium on the dead side. In this case protect it from being hit again and it may recover eventually or 2) that it was planted there as a potted tree which had overgrown its pot, and the roots started encircling the trunk. Now that it's grown, the circling roots are fatter and are choking it out. That's called girdling. You could try cutting the encircling root out, but at this point the tree will be weak and struggle, and the base of trunk may be weakened.