Hit by a car bent rim
It depends on how much the rim is bent, and if the deformation is lateral (side-to-side) or radial (in the direction of the spokes).

Take the wheel to a bike repair shop and get it evaluated. The shop may be able to true it. If it's not repairable they should be able to recommend a replacement.

As a safety precaution, don't ride the bike in the meantime.