Chief steward is a position of significant responsibility, especially in the naval industry. If you're looking for synonyms for the term, there are a few different options you could consider. For example, some similar titles include head butler, head steward, or chief purser, all of which describe a similar role to that of a chief steward. Another option might be to use more general terms like manager or supervisor, which could also be appropriate depending on the context in which the term is being used. Ultimately, the specific synonym you choose will likely depend on the particular industry or job you're referring to, as well as the level of formality you want to convey.