The phrase "backs you" is not an actual word with an antonym. However, we can break it down into its two parts - "back" and "you" - and find antonyms for each of these. The antonym for "back" is "front" or "face," which refers to the opposite direction or side of something. On the other hand, the antonym for "you" is "they" or "them," which refers to multiple people or objects instead of just one singular person. Therefore, if we put these antonyms together, we can say "they face you" as an opposite phrase to "backs you.