"Hath in keeping" is a phrase used to express possession or responsibility for something. There are several synonyms that can be used in place of "hath in keeping" such as "have in custody," "be in possession of," "maintain," "own," "hold," "keep," or "control." Each of these synonyms implies a level of responsibility or obligation towards whatever is being possessed or controlled. These synonyms can be used in a variety of contexts, from legal documents to personal relationships. Choosing the right synonym depends on the intended tone and context of the message being communicated.