"SB's" is a common abbreviated form of the possessive pronoun "somebody's". This term is often used in informal conversation or in written communication, particularly in text messages and social media posts. Some common synonyms for "SB's" include "someone's", "a person's", "an individual's", and "a human being's". Other similar phrases that can be used in place of "SB's" include "your own", "personal", and "belonging to someone". These synonyms can help add variety to your writing and communication, while still conveying the same idea or meaning. Using appropriate synonyms can also help you avoid repetition and keep your language fresh and interesting.