unacceptable

adjective

un·​ac·​cept·​able ˌən-ik-ˈsep-tə-bəl 

-ak-

: not acceptable : not pleasing or welcome

unacceptability

ˌən-ik-ˌsep-tə-ˈbi-lə-tē 

noun

unacceptably

ˌən-ik-ˈsep-tə-blē 

adverb

Synonyms of unacceptable

• wrong
• poor
• lame
• bad
• horrible
• terrible
• deficient
• awful
• unsatisfactory
• flawed
• disastrous
• pathetic

Examples of unacceptable in a Sentence

a word that is unacceptable in formal English

Some of her ideas were unacceptable to other people.

Recent Examples on the Web

In their grievance letter, the detainees called the markups an unacceptable business practice with no apparent limit. — Andrea Castillo, Los Angeles Times, 1 July 2026

During this inspection period, there were no closures or unacceptable scores. — Mary Ella Hastings july 7, Fort Worth Star-Telegram, 7 July 2026

Democrats have called it an unacceptable gift from a foreign government that is barred by the Constitution, as what is called an emolument. — Bart Jansen, USA Today, 8 July 2026

Fabian reported the threats to the police, and to Polymarket, which said that threatening a journalist was unacceptable and banned the accounts involved. — Jon Wertheim, CBS News, 28 June 2026

Word History

First Known Use

15th century, in the meaning defined above

Rhymes for unacceptable

• acceptable
• perceptible
• susceptible
• imperceptible

Kids Definition

unacceptable

adjective

un·​ac·​cept·​able ˌən-ik-ˈsep-tə-bəl 

-ak-

: not acceptable : not pleasing or welcome

unacceptably

-blē 

adverb