otiose

otiose \OH-shee-ohss\ adjective
1 : producing no useful result : futile
2 : being at leisure : idle
*3 : lacking use or effect : functionless

Example sentence: "Half the streets are cobbled and half wide, empty, modern highways at whose pretentious crossings an occasional rickshaw waits for the otiose traffic lights to change to green." (Ian Fleming, Thrilling Cities)

Did you know? "Otiose" was first used in English in the late-18th century to describe things producing no useful result. By mid-19th century, it was being used in keeping with its Latin source "otiosus," meaning "at leisure." There is also the noun form "otiosity," which predates "otiose" by approximately three centuries. That noun is rarely found in writing today, but it makes an appearance on the occasional spelling bee word list.