The phrase "most foot in mouth" implies someone has said something foolish or embarrassing. Antonyms for this phrase could include "eloquent," "diplomatic," "tactful," and "discreet." An individual who is considered "eloquent" would have a smooth and persuasive way of speaking, free of any awkward, misguided statements. A "diplomatic" speaker would maintain a level of tact and sensitivity when addressing sensitive topics, avoiding any missteps or offensive statements. Someone who is "tactful" understands how to speak with grace and sensitivity to avoid offending others. Lastly, a person who is "discreet" knows what to say and when to say it to avoid making a blunder.