When it comes to protecting oneself, there are many synonyms for the phrase "defend yourself" that can be used. Some of the most commonly used synonyms include terms such as "protect yourself," "safeguard yourself," "shield yourself," "guard yourself," and "secure yourself." Each of these terms essentially carries the same basic meaning of taking measures to prevent harm or danger to oneself, but they offer slightly different nuances in terms of the level of protection being offered. Ultimately, the choice of which synonym to use will depend on the context in which it is being used, as well as the specific connotations that the speaker or writer wishes to convey.