vain

vain, nugatory, otiose, idle, empty, hollow mean being without worth or significance. vain implies either absolute or relative absence of value <vain promises>. nugatory suggests triviality or insignificance <a monarch with nugatory powers>. otiose suggests that something serves no purpose and is either an encumbrance or a superfluity <a film without a single otiose scene>. idle suggests being incapable of worthwhile use or effect <idle speculations>. empty and hollow suggest a deceiving lack of real substance or soundness or genuineness <an empty attempt at reconciliation> <a hollow victory>.futile, vain, fruitless mean producing no result. futile may connote completeness of failure or unwisdom of undertaking <resistance had proved so futile that surrender was the only choice left>. vain usually implies simple failure to achieve a desired result <a vain attempt to get the car started>. fruitless comes close to vain but often suggests long and arduous effort or severe disappointment <fruitless efforts to obtain a lasting peace>.

Vain, vane, and vein sound the same but have different spellings and meanings. Someone who is vain is conceited. A vane, as in weather vane, is a device that shows which direction the wind is blowing. A vein is a small tube in the body that carries blood to the heart.