redshirt

1. A supporter of the Italian nationalist leader Giuseppe Garibaldi, especially a member of his thousand-man army which conquered Sicily.
2. A revolutionary or anarchist.
3. A college athlete who spends a year not participating in official athletic activities, but does not lose his or her eligibility to participate in following years. (US)
4. An unimportant character introduced only to be killed in order to underscore the peril to the important characters; an expendable character. (slang) · Sensing danger, Captain Kirk decided to beam down to the surface with Spock, McCoy, and a couple of redshirts.
5. A person responsible for loading and unloading weapons, artillery, and equipment from aircraft. (US)

Plural redshirts