hardtail
/ˈhɑːdteɪl/noun
1 US. The blue runner (fish), Caranx crysos.
2 US regional informal. A mule.
3Originally US. Originally: a motorcycle frame or rear frame section that has no rear-wheel suspension system. In later use chiefly: a motorcycle or bicycle that has suspension at the front but not at the rear.
Origin
Early 18th century; earliest use found in Natural History. From hard + tail.