noun
Refers to a person who rides a vehicle, animal, or device. Can imply skill when context suggests a 'good rider', but the core meaning is simply 'one who rides'.
このバスは乗り手が少ない。
This bus has few passengers.
彼は馬の乗り手として有名だ。
He is famous as a horse rider.
乗客 is a more formal term for 'passenger', especially on public transport. 乗り手 is broader and can include riders of animals or devices, and may carry a nuance of skill.
Compound of 乗り (continuative form of 乗る 'to ride') + 手 ('person').