IPA: /ˈɡreɪv.nəs/
KK: /ˈgreɪv.nəs/
The condition of being serious or solemn; the quality of being important or significant.
The graveness of the situation made everyone quiet and thoughtful.
Graveness is formed from "grave" (from Latin "gravis", meaning heavy or serious) and the suffix "-ness" (meaning the state or quality of). The word "graveness" refers to the quality of being serious or solemn.
Think of the word 'grave' meaning serious or heavy, and remember that 'graveness' describes the state of being serious.