red shirt
noun
1
a troublemaker US, 1967.
2
a volunteer firefighter US, 1954.
3
a college athlete who, because he did not play in his freshman year, may matriculate and play at the varsity level for a fifth year US, 1950.
4
in roller derby, a skater who engages in rough, 'bad guy' tactics US, 1999.
5
a professional wrestler who is regularly scripted to lose matches to advance the careers of other wrestlers US, 2002