IPA: /dɪˈfɪnɪtɪv.nəs/
KK: /dɪˈfɪnɪtɪvnəs/
The quality of being clear, certain, and final, leaving no room for doubt or confusion.
The definitiveness of her answer made it clear that she would not change her mind.
Definitiveness → It is formed from "definitus" (from Latin, meaning defined or limited) and the suffix "-ness" (meaning the state or quality of). The word "definitiveness" refers to the quality of being clearly defined or determined.
Think of something that is 'clearly defined' ('definitus') — the '-ness' indicates a state, so definitiveness means the state of being clearly defined.