Otiose is a formal word typically used to describe either something that serves no useful purpose, or something that has no use or effect.

// I enjoyed the storyline, but was bothered by the otiose punctuation.

// The new zoning regulations rendered their proposal for the empty lot otiose.

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"Christian Tetzlaff has only begun to play the concerto recently, but it was a masterly performance. The concentrated tension, always the hallmark of Tetzlaff’s playing, never flagged.... In other hands, an encore might have been otiose after all that. But Tetzlaff’s playing of the andante from Bach’s A minor solo sonata proved just as magical, and seemed to draw the entire hall into its hushed meditations." — Martin Kettle, The Guardian (London), 25 Aug. 2023

In this life, some pursuits seem destined to set the world on fire while others simply aren’t worth the candle. That’s where otiose comes in. The adjective traces back to the Latin noun otium meaning “leisure.” When otiose was first used in the late-18th century it described things that, like leisure (at least according to some), are pointless or otherwise produce no useful result, as in “it would be otiose to ask you about the book since you haven’t read it yet.” By the mid-19th century it was also being used to describe people who indulge a bit too much in leisure and idleness—your loafers, layabouts, and lazybones—and thus need a fire lit under them. Both otiose and the noun otiosity (which predates the adjective by several centuries) are usually found in formal writing, but should you have a burning desire to do so, feel free to drop either into casual contexts at your leisure.