The phrase "massive undertaking" means a task or project that requires a lot of effort, resources, and time to complete. It suggests that the task is challenging and requires a significant amount of work. Full definition
This was a truly massive undertaking and we're proud to bring so much popular and valuable content into the mobile era. (lawyermarketing.com)
One of von Rydingsvard's recurrent themes is the juxtaposition of organic and structural forms, transforming massive undertakings of carving and building with dense materials into elegant figures expressive of movement and gesture. (galerielelong.com)
IPCC reports are massive undertakings involving thousands of scientists, thousands of pages and thousands of references. (climatesciencewatch.org)