Messrs. is a term used as a title for a group of two or more men. It is an abbreviation for the word "messieurs", which means "gentlemen" in French. However, there are many other synonyms that can be used instead of Messrs. For instance, the title 'Mr.' itself can be used to refer to one man, or 'Gentlemen' can be used when referring to a group of men. "Guys" is also a popular informal alternative used today. Some more formal synonyms include "Sirs", "Misters", "Gents", "Senors" and "Esquires". These synonyms may vary depending on the region or culture and the context in which they are used.