Wordnet 3.0
NOUN (3)
1. 
 the state of being hollow: having an empty space within; 
2. 
 the property of having a sunken area; 
3. 
 the quality of not being open or truthful; 
 deceitful or hypocritical; 
[syn: insincerity, falseness, hollowness]
The Collaborative International Dictionary of English v.0.48:
Hollowness \Hol"low*ness\, n.
   1. State of being hollow. --Bacon.
      [1913 Webster]
   2. Insincerity; unsoundness; treachery. --South.
      [1913 Webster] holloware
WordNet (r) 3.0 (2006):
hollowness
    n 1: the state of being hollow: having an empty space within
         [ant: solidity]
    2: the property of having a sunken area
    3: the quality of not being open or truthful; deceitful or
       hypocritical [syn: insincerity, falseness, hollowness]
       [ant: sincerity]