IPA: /dɪˈsaɪdɪdnəs/
KK: /dɪˈsaɪdɪdnəs/
The state of being firm or resolute in a decision or opinion.
Her decidedness in the meeting helped the team move forward confidently.
Decidedness is formed from "decide" (from Latin "decidere", meaning to cut off or determine) and the suffix "-ness" (meaning the state or quality of). The word refers to the state of being determined or resolute in a decision.
Think of the word 'decide' which means to determine something, and remember that 'decidedness' refers to the quality of being determined.