Synonyms to waste of time

labor in vain, be found wanting, be unsuccessful, beat the air, bootless errand, come to grief, fail, fail of success, flunk, flunk out, go bankrupt, labor of Sisyphus, lash the waves, lose, lost, milk the ram, not come off, not pass, not work, snipe hunt, sow the sand, tilt at windmills, waste of breath, waste of labor, wild-goose chase, work of Penelope, wild goose chase, abortion, abortive attempt, dud, merry chase, miscarriage, miscarrying, misfire, vain attempt, wet squib