1. A condition in which something is indistinct or indefinite because of a lack of adequate illumination: The obscureness of the corner next to the library served as a place for the homeless person to stay during the very cold weather.
2. The quality of being incomprehensible or abstruse and hard to understand: Mark's task as a graduate student was to analyze the obscureness of the author's essays and to present his findings in a well-defined and coherent style.