Antonyms, or words with opposite meanings, for the term "mental processes" are often associated with physical actions or behaviors. These antonyms include terms such as physical activity, actions, movements, and behavior. Mental processes involve activities such as thinking, reasoning, and problem-solving, while their antonyms are typically more associated with physical activity or behavior. Other antonyms for mental processes might include terms like mindlessness or absence of thought. However, it's important to note that antonyms can be relative and subjective in nature, and the opposite of mental processes may vary depending on the context of the situation or the perspective of the individual.