Vain, nugatory, otiose, idle, empty, hollow are comparable when they mean devoid of worth or significance.
Something vain (see also FUTILE ) is devoid of all value, either absolutely because worthless, superfluous, or unprofitable or relatively because there are other things which are of infinitely greater value, greater necessity, or greater profitableness.
Something nugatory is trifling or insignificant or, especially in legal use, inoperative.
Something otiose has no excuse for being or serves no purpose and is usually an encumbrance or a superfluity.
Something idle has no solidity, either being baseless or groundless or being incapable of having any worthwhile effects or result.
Something empty or hollow is destitute of substance or reality and is only apparently or deceivingly sound, real, worthwhile, genuine, or sincere.