"Think on one's feet" is an idiomatic expression that means to quickly and cleverly adapt to unexpected situations or to find solutions to problems without much preparation. Synonyms for this term include "quick-witted," "nimble-minded," "fast-thinking," "resourceful," "adaptable," "ingenuity," "sharp," "alert," "resourceful," and "improvisational." When someone is "thinking on their feet," they are able to come up with creative ideas and solutions on the spot. It's an important skill in many fields, including business, education, and entertainment, and can enhance someone's problem-solving abilities in countless situations. To effectively "think on one's feet," a person needs to have a combination of knowledge, creativity, and adaptability.