"Y'" is a casual and informal abbreviation for the word "you." It is often used in online communication, texting, and social media platforms. If you are looking for synonyms for "y'," you may use words like "yourself," "thyself," "your person," "your being," or "you-wards." These synonyms retain the same meaning and formality level as "y'" and can be useful when drafting formal documents or emails. Additionally, they provide a slightly different tone or nuance that could affect how your message comes across. Regardless of the synonym you choose, be mindful of context and audience when using casual or colloquial language in professional settings.