mu·ley(myo͞o′lē, mo͝ol′ē, mo͞o′lē)
Having no horns: muley cattle.
n. pl. mu·leys
An animal without horns, especially a cow.
[From Irish Gaelic maol (from Old Irish mael) or from Welsh moel, bald, hornless.]
(Animals) (of cattle) having no horns
(Animals) any hornless cow
[C16: variant of dialect moiley, from Gaelic maol, Welsh moel bald]
mul•ey(ˈmyu li, ˈmʊl i)
(of cattle or deer) hornless; polled.
[1565–75; variant of dial. moiley < Irish maol or Welsh moel bald, hornless]
A dictionary definition is “naturally hornless,” and indeed hornless cows, particularly hornless old milk cows, were sometimes called muleys. However, the term was also applied to other things that appeared to be missing some feature. One example was the muley cultivator, which was a horse-drawn cultivator designed to not have a tongue.