There are many synonyms for the word "YABD" that can be used in place of the four-letter acronym. Some possible options include "you're a big deal," "you're awesome," "you're brilliant," and "you're the best." Other synonyms might include "you're fantastic," "you're amazing," "you're incredible," or "you're outstanding." Depending on the context, it may also be appropriate to use synonyms like "you're remarkable," "you're exceptional," "you're impressive," or "you're noteworthy." Ultimately, the choice of synonym will depend on the speaker's tone, the recipient's personality, and the situation at hand.