1. lacking intelligence or good judgment; stupid
Usage: informal
2. literally without a brain
Usage: literal; biological

Examples

• That was a brainless decision to drive without checking the weather.
• The movie was full of brainless humor that made everyone laugh.
• He made a brainless mistake by forgetting his passport.
• The jellyfish is a brainless creature that relies on simple reflexes.
• Her brainless comment embarrassed everyone at the meeting.
• The brainless action hero charged into danger without thinking.
• Scientists study brainless organisms to understand basic life functions.