Antonyms are words that have opposite meanings to each other. The phrase "where is ats" can be negated with antonyms like "here is not ats" or "ats is not here". Other antonyms for "where" can include "nowhere", "anywhere else", "far away from", or "not in this vicinity". Meanwhile, antonyms for "is" can include "is not", "isn't", "wasn't", or "hasn't been". Combined, these antonyms can be used to express the opposite or lack of knowledge about the whereabouts of "ats".