ineffective

adjective

in·​ef·​fec·​tive ˌi-nə-ˈfek-tiv 

1

: not producing an intended effect : ineffectual

ineffective lighting

an ineffective treatment

2

: not capable of performing efficiently or as expected : incapable

an ineffective executive

ineffectively adverb

ineffectiveness noun

Synonyms of ineffective

• unsuccessful
• inefficient
• counterproductive

Examples of ineffective in a Sentence

The treatment was ineffective against the disease.

an ineffective effort to reduce unemployment that only spurred inflation

Recent Examples on the Web

In May, a judge ruled that Celester McKinney received ineffective assistance of counsel in connection with his 1997 conviction, sending that case back to the Kansas Court of Appeals. — Ben Wheeler, Kansas City Star, 12 Aug. 2026

Models with extremely strong suction can harm delicate bugs, while those with tiny nozzles will be ineffective against large spiders, palmetto bugs and similarly sized insects. — Bestreviews, Mercury News, 11 Aug. 2026

Dawicki hopes the test will reduce the unnecessary use of antibiotics, and slow the current march toward antibiotic resistance that has already rendered several antibiotics ineffective. — Alice Park, Time, 7 Aug. 2026

But the difference isn't so stark as to render CDs ineffective now. — Matt Richardson, CBS News, 6 Aug. 2026

Word History

First Known Use

1649, in the meaning defined at sense 1

Rhymes for ineffective

• imperfective
• intellective
• introspective
• irrespective
• nondirective
• nonselective
• retrospective
• unreflective
• advective
• affective
• collective
• connective

Kids Definition

ineffective

adjective

in·​ef·​fec·​tive ˌin-ə-ˈfek-tiv 

1

: not producing the desired effect

an ineffective law

2

: not performing as well as expected or needed

an ineffective leader

ineffectively adverb

ineffectiveness noun