unacceptable

British  

/ ˌʌnəkˈsɛptəbəl /

adjective

1. not satisfactory; inadequate

   the standard was wholly unacceptable

2. intolerable

   hitting children is unacceptable

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Explanation

Something unacceptable is not okay — it's objectionable or displeasing. Hey, are you yelling in the library? That's unacceptable! If a student's behavior is unacceptable, she may get detention or be sent to the principal's office. And if a restaurant patron's meal is unacceptable, he has every right to ask his server for something else. The adjective unacceptable adds the "not" prefix un- to acceptable, "suitable, adequate, or pleasing." We can trace the roots back to the Latin acceptare, "take or receive willingly."

Example Sentences

"Unacceptable and criminal behaviour has absolutely no place in our Armed Forces and any reporting of a serious crime by serving personnel is investigated independently from their chain of command," the MoD said.

From BBC • Jun. 8, 2025

“I hurt for my France. Unacceptable situation. All my thoughts go to the family and loved ones of Nael, this little angel gone much too soon,” he tweeted.

From Seattle Times • Jun. 28, 2023

The board suspended De Zeeuw pending an investigation by the university’s Complaints Committee for Unacceptable Behaviour, which issued its verdict last week.

From Science Magazine • Oct. 25, 2022

"This has happened on a number of occasions, I haven’t seen with any other candidate. It’s not just a slip-up. Unacceptable."

From Fox News • Nov. 18, 2019

"The Young Wolf has sent us terms, you see. Unacceptable terms, to be sure, but still, a beginning. Would you care to see them?"

From "A Clash of Kings" by George R.R. Martin

Related Words

• distasteful
• improper
• inadmissible
• objectionable
• offensive
• repugnant
• undesirable
• unsatisfactory