trackless; without rails
Literal meaning: lacking tracks or rails. Used for vehicles or systems that do not follow a fixed path.
A trackless tram runs without using rails.
reckless; dissipated; unrestrained
Figurative extension: acting without moral or social guidelines, often implying a wild or self-indulgent lifestyle.
His reckless lifestyle worried those around him.
wild behavior; reckless conduct
Compound of 無 (without) and 軌道 (track, orbit). The figurative sense derives from the idea of not following a set path.