Lastly is a transitional word used to signify the final point in a series of ideas or actions. Synonyms for lastly include "finally," "ultimately," "in the end," "eventually," and "at last." These words are commonly used to convey the conclusion of something or the end of a thought or event. Other synonyms for lastly may include "conclusively," "endwise," and "windup." Adding variety to your writing by using synonyms for lastly can make your work more engaging and dynamic to read. Use these alternative words to signal the end of your argument or story or to communicate the last point in a sequence of ideas.