adj. 1. Cloudy, misty, or hazy. 2. Lacking definite form or limits; vague: nebulous assurances of future cooperation. 3. Of, relating to, or characteristic of a nebula. [Middle English, from Latin nebulōsus, from nebula, cloud; see nebh- in the Appendix of Indo-European roots.] nebu·lous·ly adv. nebu·lous·ness n. |
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