"Furiousnesses" is a highly unusual word, and as such finding synonyms for it is a challenging task. Nonetheless, there are several terms that could be used to convey a similar sentiment. For instance, "anger", "rage", "fury," and "outrage" are all words that could be used to describe a state of extreme anger or frustration. Alternatively, "wrath," "ire," "exasperation," and "indignation" are words that could describe a vexed or indignant mood. While none of these terms is an exact synonym for "furiousnesses," they all capture a similar sense of intense emotional disturbance or discontent.