Adjective
Having no rider; as, a riderless horse.
Source: Webster's dictionaryThe riderless horse, flanked by two Lance Corporals of the police Mounted Branch, stood just the east of the tent; further in the northeastern corner of the compound was the statue of the father of trade unionism in Guyana, Hubert Nathaniel Critchlow. Source: Internet
The riderless horse approaches the memorial. Source: Internet
The riderless horse is the Camp Verde Cavalry honoring one of its own who is no longer with it. Source: Internet