"Hath in hand" means having something under control, having possession or ownership of something, or having the power to make decisions about something. Antonyms for this term could include "at a loss," "under someone else's control," "without possession," or "lacking decision-making power." Other antonyms might be "at the mercy of," "powerless," or "disadvantaged." Essentially, any terms that suggest an absence of control, ownership or power would be antonyms for the concept of having something "hath in hand." It is helpful to consider the context in which this phrase is used to select the most appropriate antonyms.