IPA: /səˈpriː.mə.nəs/
KK: /səˈpriːm.nəs/
The quality or state of being the highest in rank, authority, or power.
The supremeness of her leadership was recognized by everyone in the organization.
Supremeness is formed from "supreme" (from Latin "supremus", meaning highest or utmost) and the suffix "-ness" (meaning the state or quality of). The word "supremeness" refers to the state of being supreme or the highest in rank or quality.
Think of 'supreme' meaning the highest, and '-ness' indicating a state. This helps you remember that 'supremeness' refers to the state of being the highest.