Definition of: understudy

(un′dər·stud′ē) v.t. & v.i. ·stud·ied, ·stud·y·ing
1. To study (a part) in order to be able, if necessary, to take the place of the actor playing it.
2. To act as an understudy to (another actor).
—noun plural ·stud·ies
1. An actor or actress who can take the place of another actor in a given role when necessary.
2. A person prepared to perform the work or fill the position of another.