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

Two attempts at divorce by Imogen were unsuccessful, the last one having been a month ago. — Jeanne Phillips, Mercury News, 13 Aug. 2026

In 1953, Castro and more than 100 others attacked the Moncada Barracks in Santiago de Cuba in an unsuccessful attempt to overthrow dictator Fulgencio Batista. — ABC News, 13 Aug. 2026

Phone and email attempts to reach a Tlaib spokesperson in recent days were unsuccessful. — Anthony Man, Sun Sentinel, 13 Aug. 2026

DeLong said that police had contact with the father as recently as the last few weeks and that officers have responded to the area of the family’s home in the past based on reports of gunfire but were unsuccessful finding evidence. — Dennis Romero, NBC news, 12 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