The word "sermonise" means to preach or lecture someone in a way that can be seen as patronizing. However, there are several synonyms for the same word, which can be used to express the same meaning in different ways. Some synonyms for "sermonise" include "lecture," "preach," "discourse," "advise," "guide," "instruct," and "chastise." Each of them has its own unique usage and connotation, but they all convey a sense of instructing someone else on how to behave or think in a way that could be construed as condescending. Therefore, it is essential to use these synonyms carefully, depending on the context in which they are used.