Alfalfa or weed
These leaf pictures are consistent with a variant race of alfalfa plants. No alfalfa seed bank is pure for one plant cultivar, they are always a mix of alfalfa races and cultivars.
The leaves have teeth along the leaf margins only and this is an identifying characteristic of Medicago sativa (Alfalfa). Sweet clovers look a lot like alfalfa but they have small teeth along the entire leaf margin.
Thank you for your question.