Brainlessnesses is a word that refers to a lack of intelligence or mental capacity. The antonyms for this word would be intelligence, wit, cleverness, astuteness, intellect, and acumen. These words suggest a sharpness of the mind and an ability to think critically, solve problems, and make wise decisions. While brainlessnesses implies a deficit of cognitive skills, these antonyms speak to a range of mental abilities that are highly valued in many contexts, from school and work to social situations and personal relationships. By contrast, brainlessnesses suggests a limitation that can be frustrating or even harmful in certain situations.