Wave
Onshore wind
Wind blowing from the water toward the land, which roughens the surface and degrades the wave, considered unfavorable.
Onshore wind blows from the water toward the land. It tends to push into the back of the wave and chop up the surface, making the wake messy and harder to ride, which is why it's considered not ideal. Choppy water from onshore wind breaks up the clean face and makes finding and holding the push more difficult.
Riders often seek sheltered water or a run direction that minimizes onshore wind effects to keep the wave as clean as possible.