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 number of tasks completed, time required for individual activities, frequency of human intervention, and ability to recover from unsuccessful attempts would provide useful measures of their effectiveness. — Jijo Malayil, Interesting Engineering, 2 Nov. 2026

Attempts by the South Florida Sun Sentinel to reach Filgueiras’ relatives were unsuccessful. — Zoey Thomas, Sun Sentinel, 2 Nov. 2026

Her chances at having a baby only seemed to worsen in 2014, when a colorectal surgeon attempted to reposition her stoma — an opening in the abdomen through which waste exits the body — to make pregnancy possible, but the surgery was unsuccessful. — Toria Sheffield, PEOPLE, 1 Nov. 2026

After an unsuccessful two-point try by Miami, Rhamondre Stevenson recovered Bradley Pinion's onside kick, and New England kept the ball from there. — ABC News, 1 Nov. 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