IPA: //ʌnˈjuːʒuəl.nəs//
KK: /ʌnˈjuːʒuəl.nəs/
The quality or state of being different from what is normal or expected.
The unusualness of the painting caught everyone's attention at the gallery.
Unusualness → It is formed from "un-" (meaning not), "usual" (from Old French *usuel*, meaning customary or habitual), and "-ness" (meaning the state or quality of). The word "unusualness" refers to the state of being not customary or not habitual.
Think of 'not' ('un-') being added to 'customary' ('usual') to describe something that is in a state of being different or rare.