Have you ever watered a potted plant and seen the water "float?" It's very frustrating, because as much as you water, the soil repels the liquid. This is called hydrophobic soil. It can arise in natural settings from wildfires when waxy substances from plants infiltrate the upper soil layer.
In a home garden it's most common in potted plants. The plant will essentially die from underwatering. No matter how much you water it, the water just runs over the pot sides or between the soil and pot to the ground. Soil wetting agents are available, but not usually necessary on a small scale.
Instead, first remove the top inch or so of soil; if water is absorbed by the remaining soil, just replace the inch you removed with fresh soil. If not, you can repot the entire plant with fresh soil, or place it in a few inches of water until the soil absorbs the water from the bottom up.
I've seen potting soil that was so dried out, it could not be rehabilitated to absorb water, even with the addition of organic material, peat or coir. This soil was given new life in the compost heap.