"Preach" is a powerful word that often denotes speaking from a position of authority or promoting a particular set of beliefs. Some synonyms for "preach" include "advocate," "proclaim," "declare," "teach," and "lecture." When we advocate, we are acting as a supporter or promoter of a particular cause or idea. Proclaiming refers to making a declaration or announcement in a formal or public way. Declaring is similar to proclaiming, but it emphasizes stating something definitively or with authority. Teaching involves instructing or guiding someone in a specific subject or skill. Lastly, lecturing involves giving a long, serious talk that is intended to inform or educate an audience.