otiose, ineffectual, unproductive, useless, unavailing, fruitless, bootless, vain, sleeveless, unfutile, more...

productive, effective, useful, successful, fruitful

futilely, futility, more...

all for nothing,   a waste of time,   having no effect,   wasted effort,   like wasted money,   trying but failing,   doomed to failure,   in vein,   no point in,   they're hopeless