# brainless

/ˈbɹeɪnɫɪs/ (US) · /bɹˈeɪnləs/ (UK) · CEFR B2 · Adjective

Source: https://englishreference.com/word/brainless
Updated: 2026-05-28

## Definition

describing someone who is very stupid or lacks common sense. It is a strong word that people use to show they think someone is acting like a fool.

For teachers: lacking intelligence or common sense; acting in a foolish or thoughtless manner. Often carries a derogatory or dismissive tone in informal contexts.

## Examples

- It was a brainless mistake to leave the keys in the car.
- The politician made a brainless comment about the economy that immediately cost him his job.
- While the plan seemed brilliant on paper, the brainless execution led to a total collapse of the project's budget and timeline.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.