When it comes to marine vessels, out rigger refers to a supporting structure that extends out from the side of the boat to provide stability. If you're looking for synonyms for this commonly used term, you might consider "outrigger boom" or simply "outrigger arm." In some settings, the outrigger may also be referred to as a "float" or a "crossbeam," depending on its specific shape and function. Other possible synonyms could include "cantilever," "bracket," "stabilizer," or "strut," all of which could be used to refer to a similar structure designed to provide support and balance on a boat or other watercraft.