This word is not acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

n. The state or condition of being unflinching; steadfastness, resoluteness.

"Before her landscape series, Ms. Jones created many expressionist self-portraits that lent an unflinchingness to her jagged-to-swirly mark-making, much of it with big oil-paint crayons."