The word "they're" is a contraction of "they" and "are." Some synonyms for "they're" include "they are," "they have," "they've," "they exist," "they live," and "they stay." It is important to note that not all of these synonyms have the same meaning as "they're", and should be used in the appropriate context. For example, "they exist" and "they live" imply a more solid, tangible presence than "they're." Synonyms can be a great way to vary your language usage and avoid overusing certain words in your writing.