unsuccessful

adjective

un·​suc·​cess·​ful ˌən-sək-ˈses-fəl 

: not successful : not meeting with or producing success

unsuccessfully

ˌən-sək-ˈses-fə-lē 

adverb

Synonyms of unsuccessful

• futile
• useless
• abortive

Examples of unsuccessful in a Sentence

His last novel was unsuccessful.

an unsuccessful attempt to fix the faucet ourselves

Recent Examples on the Web

The new guidelines follow an unsuccessful attempt in the General Assembly this spring to impose a statewide bell-to-bell ban on cellphone use in public schools. — Theo Peck-Suzuki, Hartford Courant, 6 Aug. 2026

Ruben Altidore, 36, repeatedly hacked at his sister in her bedroom in an unsuccessful attempt to kill her on Monday in Margate, which is located about 40 miles north of Miami, according to an arrest report obtained by WPLG. — Landon Mion, FOXNews.com, 6 Aug. 2026

If those efforts are unsuccessful, personnel from the Avalon Fire Department and Los Angeles County’s Baywatch would be able to provide some level of emergency medical treatment while patients await transportation across the Catalina Channel. — Connor Sheets, Los Angeles Times, 6 Aug. 2026

The phishers were unsuccessful in both cases, city officials said. — Nate Gartrell, Mercury News, 6 Aug. 2026

Word History

First Known Use

1617, in the meaning defined above

Phrases Containing unsuccessful

• make an unsuccessful run for

Rhymes for unsuccessful

• distressful
• successful
• stressful

Kids Definition

unsuccessful

adjective

un·​suc·​cess·​ful ˌən(t)-sək-ˈses-fəl 

: not successful : not having or producing success

unsuccessfully

-fə-lē 

adverb