adjective

failing to achieve the desired results; unproductive or useless.

his fruitless attempts to publish poetry

futile,vain,in vain,to no avail,to no effect,idle,pointless,useless,worthless,needless,wasted,hollow,ineffectual,ineffective,inefficacious,unproductive,unrewarding,profitless,unsuccessful,unavailing,barren,for naught,abortive,bootless