When it comes to synonyms for the phrase "let slip," there are many variations that can be used depending on the context. Some common synonyms include "blurt out," "reveal," "disclose," "divulge," and "uncover." These terms all suggest that one is sharing information that they may not have intended to share, either accidentally or intentionally. Other synonyms might include "expose," "betray," "give away," or "admit," which all convey a sense of revealing something that was meant to be kept secret. Ultimately, the choice of synonym will depend on the exact meaning and context of the situation in question.