In the French language, 'sois' is the second person imperative form of the verb 'être', which means 'to be'. This word is used to instruct or command someone to be or to act in a certain way. There are several synonyms for 'sois' that can be used in different contexts. Some of these synonyms include 'deviens' which means 'become', 'agis' which means 'act', 'fais' which means 'do', 'porte-toi' which means 'behave', and 'manifeste' which means 'show'. These synonyms can be helpful when trying to convey a message or an instruction to someone in a more effective and varied way.