Inefficacious

Part of speech: adjective

Definitions

1. Lacking the power to produce a desired effect or result; not capable of achieving what is intended
2. Being unable to bring about the intended outcome or effect means something is not successful in accomplishing its goal
3. When something fails to deliver the expected result or to be effective, it is deemed unproductive or insufficient

Etymology: "Inefficacious" is simply "efficacious" with the negating prefix "in-" attached. The base word traces back to Latin "efficere," meaning "to accomplish" or "to bring about," built from "ex," "out," and "facere," "to make or do." The Latin "efficax," "effective," passed into English through Old French "efficacieux," and "efficacious" took shape in English by adding the Old French-derived "-ous" ending. Its Latin ancestry runs through the verb "facere," the same root that gives English "fact" and "factory." The prefix "in-" is the familiar Latin negator found in words like "inactive" and "invisible," and it was attached to "efficacious" in English. The result describes something that fails to produce the result it was meant to produce, such as a medicine that does nothing for the illness it targets.

Synonyms: ineffective, inefficiency, unproductive, futile, fruitless

Antonyms: effective, efficient, productive, potent, beneficial