inefficacious

American  

[in-ef-i-key-shuhs] / ˌɪn ɛf ɪˈkeɪ ʃəs /

adjective

1. not able to produce the desired effect; ineffective.

---

inefficacious British  

/ ˌɪnɛfɪˈkæsɪtɪ, ˌɪnɛfɪˈkeɪʃəs, ɪnˈɛfɪkəsɪ /

adjective

1. failing to produce the desired effect

---

Other Word Forms

• inefficaciously adverb
• inefficaciousness noun
• inefficacity noun
• inefficacy noun

Etymology

Origin of inefficacious

First recorded in 1650–60; in- ³ + efficacious

Example Sentences

Most nostrums hit at only one of the causes and so are frequently inefficacious.

From Time Magazine Archive

Remedies for the starling plague were suggested, some facetious, some earnest, all equally inefficacious.

From Time Magazine Archive

Every argument was brought forward to induce him to stay in La Rochelle, but every argument proved inefficacious.

From The Huguenot: (Volumes I-III) A Tale of the French Protestants. by James, G. P. R. (George Payne Rainsford)

Had his aunt merely told him that his present would be inefficacious, he would have taken that assurance as being simply her opinion, and would have still entertained some hopes in the diamonds.

From Ayala's Angel by Trollope, Anthony

They have used the leaves in such large proportion, that the doses have been sufficient, or more than sufficient, even in their most inefficacious state.

From An Account of the Foxglove and some of its Medical Uses With Practical Remarks on Dropsy and Other Diseases by Withering, William