IPA: /ˈreɪn.ləs/
KK: /ˈreɪn.ləs/
Not having any reins, which are used to control animals, especially horses; therefore, it is free and not restrained.
The horse ran reinless across the open field, enjoying its freedom.
Reinless → It is formed from "rein" (from Old French *reine*, meaning a strap used to control a horse) and "-less" (meaning without). The word "reinless" means without reins, indicating a lack of control or guidance.
Imagine a horse that is 'without' ('-less') its 'reins' — this helps you remember that 'reinless' means lacking control.