"Get feet" is an idiomatic expression that typically means to gain a foothold or establish oneself in a particular setting. Antonyms for "get feet" could include "lose ground," "retreat," "recede," or "backpedal." These words suggest the opposite of gaining a foothold, instead indicating a loss of progress, withdrawal or defeat. Other antonyms for "get feet" might include "falter," "flounder," or "waver," which imply a lack of stability or confidence in one's position. Overall, antonyms for "get feet" indicate a lack of advancement, stability or success in achieving one's goals or objectives.