not effective

ADJECTIVE

ineffective

Synonyms

STRONGEST

feeble fruitless futile impotent inadequate incompetent indecisive ineffectual inefficient inept limited null powerless unable unproductive unprofitable unsuccessful worthless

WEAK

abortive anticlimactic barren bootless defeasible emasculate epicene feckless forceless idle inefficacious inferior innocuous inoperative lame neutralized no-go nugatory paltry slack-spined spineless unavailable unavailing unfruitful vain void withered

Antonyms

STRONGEST

able adequate capable competent dexterous effective effectual efficient expert fit fruitful potent powerful productive profitable skillful strong successful sufficient useful valuable worthwhile worthy

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

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not effective

The report's authors said their findings were consistent with two other studies and, when taken together, provided "strong evidence that the MenB vaccine is not effective for gonorrhea prevention".

From BBC ● Jul. 8, 2026

That’s not effective fraud protection — that’s a broken system that is wasting money and creating friction with customers and vendors.

From MarketWatch ● Apr. 22, 2026

"These are symbolic gestures of intimidation intended to instil fear, but they are not effective."

From Barron's ● Jan. 9, 2026

Stella said: "Unfortunately, we also saw that, because of the car operating window and the circuit characteristics, most of these actions were not effective enough in reducing porpoising."

From BBC ● Nov. 27, 2025

“Or it’s not effective on egglets,” Jordie puts in.

From "Linked" by Gordon Korman

not effective

Example Sentences

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