Monumental

Full definition of monumental

Adjective

1. In the manner of a monument.
2. Large, grand and imposing. Fitting to be a monument to someone or something.
3. Taking a great amount of time and effort to complete.
• 2012, w, Well-connected Brains, Creating a complete map of the human connectome would therefore be a monumental milestone but not the end of the journey to understanding how our brains work.
4. "a monumental task"