Entry 2 senses Webster, 1913 Nebulous /nĕb'-yəl-əs/ · Neb·u·lous · IPA /ˈnɛbjʊləs/ 01 a. Cloudy; hazy; misty. 1. Cloudy; hazy; misty. 2. Of, pertaining to, or having the appearance of, a nebula; nebular; cloudlike.(Astron.)