uselessness

Synonyms:
1. fruitless, profitless, valueless, worthless, inutile. Useless, futile, ineffectual, vain refer to that which is unavailing. That is useless which is unavailing because of the circumstances of the case or some inherent defect: It is useless to cry over spilt milk. Futile suggests wasted effort and complete failure to attain a desired end: All attempts were futile. That which is ineffectual weakly applies energy in an ill-advised way and does not produce a desired effect: an ineffectual effort. That which is vain is fruitless or hopeless even after all possible effort: It is vain to keep on hoping. 2. unserviceable, unusable.

Antonyms:
1. effective.