Antonyms for the phrase "becoming similar" include words like diverging, separating, dissimilar, different, and unique. Diverging means to move away from each other, while separating refers to the act of pulling apart. Dissimilar means being unlike or different, and different is the opposite of alike. Unique suggests being nothing like anything else, and the opposite of similar. Antonyms for becoming similar can be used when there is a need to emphasize the differences between two things, as opposed to focusing on their similarities. It's essential to understand that opposite words can help us to better understand the range of meaning of the original word.