Part of speech: Adjective
producing no result or effect
Example: a futile effort; the therapy was ineffectual; an otiose undertaking; an unavailing attempt
Unavailing, Futile, Ineffectual, Vain, Fruitless
The word "futile" comes from Latin fūtilis, which comes from Middle French futile.
Legal and medical professions still use Latin phrases because of its precision and historical authority.