working title

Translations
рабочее название
The film is currently being shot under the working title 'Project X'.
Фильм в настоящее время снимается под рабочим названием 'Проект Х'.
Definitions
A temporary name given to a project, such as a book, film, or other creative work, while it is still in development and before a final title is decided.
Words
working

adjective
рабочее
title

noun
название