IPA: /ˈmæsɪv.nəs/
KK: /ˈmæsɪvnəs/
The quality or state of being very large or heavy.
The massiveness of the mountain made it a popular destination for hikers.
Massiveness → It is formed from "mass" (from Latin *massa*, meaning a lump or bulk) and the suffix "-ive" (meaning having the nature of) combined with the suffix "-ness" (meaning the state or quality of). The word "massiveness" refers to the quality of being large or bulky in size or volume.
Think of a 'lump' or 'bulk' ('mass') that has a certain quality ('-ive') and state ('-ness') — this helps you remember that massiveness means the quality of being large or bulky.