understudy

UK: /ˈʌndə^rstʌdi/ US: /ˈʌndɚˌstʌdi/ ,(un′dər stud′ē)

Inflections of 'understudy' (n): npl: understudies

Inflections of 'understudy' (v): (⇒ conjugate)

understudies

v 3rd person singular

understudying

v pres p

understudied

v past

understudied

v past p

WordReference Random House Learner's Dictionary of American English © 2026

un•der•stud•y /ˈʌndɚˌstʌdi/   n., pl. -stud•ies, v., -stud•ied, -stud•y•ing. 
n. [countable]

1. Show Business a performer who learns the role of another in order to serve as a replacement if necessary.

v. [~ + object]

2. Show Business to learn (a role) in order to replace the regular performer when necessary.
3. Show Business to act as understudy to (a performer).

See -stud-.

WordReference Random House Unabridged Dictionary of American English © 2026

un•der•stud•y  (un′dər stud′ē), v., -stud•ied, -stud•y•ing, n., pl. -stud•ies. 
v.t. 

1. Show Business to learn (a role) in order to replace the regular actor or actress when necessary.
2. Show Business to act as understudy to (an actor or actress):
   to understudy the lead.

v.i. 

3. Show Business to act or work as an understudy.

n. 

4. Show Business a performer who learns the role of another in order to serve as a replacement if necessary.

• under- + study 1870–75

Collins Concise English Dictionary © HarperCollins Publishers::

understudy / ˈʌndəˌstʌdɪ/ verb ( -studies, -studying, -studied)

1. (transitive) to study (a role or part) so as to be able to replace the usual actor or actress if necessary
2. to act as understudy to (an actor or actress)

noun ( -studies)

1. an actor or actress who studies a part so as to be able to replace the usual actor or actress if necessary
2. anyone who is trained to take the place of another in case of need