1. 
[syn: self-consciousness, uneasiness, uncomfortableness]
2.  self-awareness plus the additional realization that others are similarly aware of you; 
The Collaborative International Dictionary of English v.0.48:
Self-consciousness \Self`-con"scious*ness\, n.
   The quality or state of being self-conscious.
   [1913 Webster]
WordNet (r) 3.0 (2006):
self-consciousness
    n 1: embarrassment deriving from the feeling that others are
         critically aware of you [syn: self-consciousness,
         uneasiness, uncomfortableness]
    2: self-awareness plus the additional realization that others
       are similarly aware of you [ant: unselfconsciousness]