Astucious, which means clever or cunning, has a few antonyms that express the opposite meaning. One of them is foolish, which describes someone who lacks good judgment or common sense. Another antonym for astucious is obtuse, which means dull or slow-witted. Similarly, another antonym for more astucious is ignorant, reflecting a lack of knowledge or understanding. Slothful, which means lazy or slow-moving, is yet another antonym for astucious. Finally, naive, which means lacking experience or wisdom, is an antonym that refers to someone who is not very clever or streetwise. These antonyms all suggest a lack of intelligence or cunning, which contrasts with the shrewdness associated with being astucious.