1. of, relating to, or characteristic of imbecility; showing extreme stupidity or lack of intelligence
Usage: offensive when applied to people with intellectual disabilities; dated medical/psychological term

Examples

• The plan was so imbecilic that no one took it seriously.
• His imbecilic remarks made the entire meeting uncomfortable.
• That was an imbecilic decision that cost the company thousands of dollars.
• The imbecilic logic of the argument fell apart under scrutiny.
• She dismissed his imbecilic suggestions without hesitation.