Unavoidableness is a noun that describes the quality or condition of something that cannot be avoided or prevented. Some possible synonyms for this word might include inevitability, inescapability, necessity, and certainty. Each of these terms connotes a sense of inevitability or inevitableness, suggesting that the outcome or event in question is inevitable and cannot be avoided no matter what one does. Other possible synonyms might include fate, predestination, or predeterminedness, though these terms often connote a sense of determinism or lack of agency that is not necessarily present in the concept of unavoidableness. Ultimately, the choice of synonym will depend on the context in which the word is being used and the specific connotations or meanings that are desired.