(a.) of a futile effort.

abortive absurd airy apish asinine bad barren batty befooled beguiled besotted bootless brainless buffoonish catchpenny cockeyed counterproductive crazy credulous daffy daft dazed dizzy doomed doting dumb effete empty etiolated failed failing fatuitous fatuous feckless flaky flimsy fond fool foolheaded foolish foredoomed fribble fribbling frivolous frothy fruitless fuddled gaga goofy gulled hollow idiotic idle ill-advised ill-considered ill-suited ill-timed imbecile impolitic impotent improper in vain inadequate inadvisable inane inappropriate inapt incongruous ineffective ineffectual inefficacious inefficient inept inexpedient infatuated infelicitous inoperative inopportune insane insufficient invalid kooky lame light loony mad mal a propos malapropos manque maudlin miscarried miscarrying moronic nugacious nugatory nutty of no effect of no force otiose out of place profitless sappy screwy senseless sentimental shallow silly slender slight sterile stickit stillborn stupid successless superficial thoughtless trifling trite trivial unavailable unavailing unbefitting undesirable unfit unfitting unfortunate unhappy unmeet unproductive unprofitable unsatisfactory unseasonable unseemly unsuccessful unsuitable untimely unwise useless vacuous vain vapid wacky wet windy witless worthless wrong