brainless

This term carries a harsh, derogatory tone when applied to people, suggesting a complete absence of judgment or intellectual capacity. It is more aggressive than words like foolish or unwise, often implying a level of stupidity that is frustrating or inexplicable to the observer.

In a biological sense, the word is used neutrally and descriptively to categorize organisms that lack a centralized nervous system. This technical application is devoid of the judgmental quality found in the colloquial usage.