Antonyms are words that are opposite in meaning to each other. 'Am tantamount to' implies equality or sameness, so antonyms would be words that suggest the opposite, such as 'different,' 'unequal,' 'unlike,' or 'incompatible.' These words indicate a lack of similarity or equivalence between two things, and imply differences in size, quality, or value. For example, "She is unlike her sister in every way"; "Their privileges were incompatible with their responsibilities." Using antonyms can enhance communication by clarifying the meaning and promoting a more nuanced understanding of complex ideas.