【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.