na-adjective, noun
trackless; without rails
Literal meaning: lacking tracks or rails. Used for vehicles or systems that do not follow a fixed path.
無軌道電車はレールを使わずに走る。
A trackless tram runs without using rails.
na-adjective, noun
Figurative extension: acting without moral or social guidelines, often implying a wild or self-indulgent lifestyle.
彼の無軌道な生活は周囲を心配させた。
His reckless lifestyle worried those around him.