/un"deuhr stud'ee/ , v. , understudied, understudying , n. , pl. understudies .
v.t.
1. to learn (a role) in order to replace the regular actor or actress when necessary.
2. to act as understudy to (an actor or actress): to understudy the lead.
v.i.
3. to act or work as an understudy.
n.
4. a performer who learns the role of another in order to serve as a replacement if necessary.
[ 1870-75; UNDER- + STUDY ]