We found one dictionary that defines the word self-opinionatedness:

General (1 matching dictionary)

1. self-opinionatedness: Merriam-Webster

(Note: See self-opinionated as well.)

Definitions from Wiktionary (self-opinionated) ▸ adjective:  Obstinately adhering to one's own opinion. ▸ Also see self-opinionated ▸ Words similar to self-opinionatedness ▸ Usage examples for self-opinionatedness ▸ Idioms related to self-opinionatedness ▸ Wikipedia articles (New!) ▸ Popular nouns described by self-opinionatedness ▸ Words that often appear near self-opinionatedness ▸ Rhymes of self-opinionatedness ▸ Invented words related to self-opinionatedness