Missionarying refers to the act of promoting or advocating a particular belief or cause. There are various synonyms that can be used instead of the word missionarying, depending on the context. Some options include evangelizing, preaching, propagating, spreading, advancing, proselytizing, spreading the word, and sharing beliefs. Each of these synonyms conveys a similar idea to missionarying but may have slightly different implications. For example, evangelizing and preaching may suggest a religious or spiritual context, while propagating and advancing may have more secular associations. In any case, using synonyms can help to add variety and nuance to one's writing or conversation.