There are several antonyms for the idiomatic phrase "foot-in-mouth," meaning to say something embarrassing, inappropriate, or unintentionally offensive. One is "diplomatic," characterized by tact, sensitivity, and discretion in communication. Another is "polite," referring to courteous, respectful, and thoughtful behavior. A third antonym is "eloquent," indicating the ability to express oneself fluently and persuasively. Finally, "mindful" can be used as an antonym, conveying awareness, attentiveness, and consideration. By choosing one of these alternative expressions, speakers can avoid the awkwardness of putting their foot in their mouth and instead communicate effectively and respectfully.