The Collaborative International Dictionary of English v.0.48:

Nullity \Nul"li*ty\ (n[u^]l"l[i^]*t[y^]), n.; pl. Nullities.
   [LL. nullitias, fr. L. nullus none: cf. F. nullit['e] . See
   Null.]
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   1. The quality or state of being null; nothingness; want of
      efficacy or force.
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   2. (Law) Nonexistence; as, a decree of nullity of marriage is
      a decree that no legal marriage exists.
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   3. That which is null.
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            Was it not absurd to say that the convention was
            supreme in the state, and yet a nullity? --Macaulay.
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