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

Tell them that their behavior is embarrassing and unacceptable. — Harriette Cole, Mercury News, 23 July 2026

Other officials told me that, in meetings of White House staff, Finer, the deputy national-security adviser, often asked what civilian death toll would be deemed unacceptable. — David D. Kirkpatrick, New Yorker, 20 July 2026

That’s unacceptable to Scharf, who knows everyone in the business and recognizes that there is poachable talent at rival banks. — Jim Cramer, CNBC, 20 July 2026

At the 2025 Ryder Cup at Bethpage Black, it was widely reported that some unruly fans yelled unacceptable things towards him, but instead of handling , McIlroy snapped, screaming obscenities right back. — Ian Miller Outkick, FOXNews.com, 19 July 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