Antonyms for "most big talking" could include words such as "reserved," "humble," "modest," "unassuming," and "meek." These words describe individuals who are not boastful or arrogant in their speech and actions, and instead, are characterized by a level of modesty and humility. They are less likely to exaggerate their achievements or abilities and are often more introspective in their thoughts and behaviors. People who are most big talking have a tendency to overemphasize their accomplishments or abilities, often to the point of being insincere or disingenuous. By contrast, antonyms for this phrase highlight the value of authenticity, sincerity, and humility in interactions with others.