Leatherneck is a slang term used to refer to a member of the United States Marine Corps. However, if you are looking for synonyms for this unique word, there are a few options available. Some of the most common alternatives include "jarhead," "devil dog," and "grunt." Jarhead is a term that has been used colloquially within the Marine Corps to describe newly enlisted soldiers who have just had their heads freshly shaved. Devil dog is a term that owes its origin to the Marine Corps' reputation for toughness and fighting ability. Grunt is also a slang term that is used to describe soldiers in any branch of the military who are responsible for carrying heavy equipment.