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

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

Apart from polluting ecosystems and leaving toxic residues on human food sources, these aggressive chemicals drive pests to develop genetic resistance, rendering treatments ineffective over time. — Mrigakshi Dixit, Interesting Engineering, 4 Aug. 2026

The government’s efforts to alleviate the crisis have been ineffective. — Alexis Okeowo, New Yorker, 3 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