inefficacious
|in-ef-fi-ca-cious|
/ˌɪnɪfɪˈkeɪʃəs/
not producing the intended effect
Etymology
'inefficacious' originates from Latin, specifically formed from the prefix 'in-' meaning 'not' + 'efficacious' (from Latin 'efficax'), where 'efficax' is related to 'efficere' meaning 'to bring about or accomplish'.
'inefficacious' developed from Late Latin 'inefficax' (in- + efficax), passed into medieval/modern Romance forms such as Old/Middle French 'inefficace', and was adopted into English as 'inefficacious' (modeled on 'efficacious' with the negative prefix 'in-').
Initially it meant 'not accomplishing or bringing about an effect' and over time has retained essentially the same meaning of 'not producing the desired effect'.
Meanings by Part of Speech
Adjective 1
not producing the desired or intended effect; ineffective.
The new policy proved inefficacious in reducing emissions.
Synonyms
Antonyms
Adjective 2
lacking the power, capacity, or ability to produce a specific result; powerless to accomplish an intended outcome.
Her attempts to mediate the dispute were inefficacious.
Synonyms
Antonyms
Last updated: 2025/12/17 03:51