Embark means to begin a journey or to start a new venture. There are a variety of synonyms that can be used instead of embark depending on the context and tone of the sentence. Some alternatives to the word include "commence," "launch," "initiate," "start off," "set out," "begin," "undertake," "enter upon," "proceed," "embark on," "take up," "set on foot," "kick off," and "inaugurate." Each of these synonyms conveys a similar sense of starting or commencing something new, but they may be better suited to different types of writing or speaking.