The word 'nitwittedness' refers to a lack of intelligence or foolishness. Antonyms for this word would, therefore, refer to an abundance of intelligence and opposite to foolishness. These antonyms include words such as intelligence, wisdom, brilliance, smartness, shrewdness, astuteness, cleverness, sagacity, and perspicuity. These words refer to a person's level of intelligence, whether it is inherent or learned through experience. Using these words not only provides an effective contrast to the negative connotation of 'nitwittedness' but also highlights the positive attributes of a person who possesses these qualities. A person's intelligence quotient is essential, and it's a vital tool for success in every path of life.