The word "monologuize" means to deliver a monologue, which is a long speech by one person. Some synonyms for "monologuize" include soliloquize, speak at length, pontificate, lecture, sermonize, declaim, and expatiate. These words carry different connotations and may be used in different contexts. For example, "soliloquize" implies that the speaker is talking to themselves, while "pontificate" implies a level of arrogance or self-importance. "Lecture" and "sermonize" imply a desire to educate or persuade an audience, while "declaim" and "expatiate" suggest a more formal or rehearsed delivery. Overall, these synonyms can be used to convey different shades of meaning when describing lengthy speeches by a single speaker.