The Collaborative International Dictionary of English v.0.48:

Palliative \Pal"li*a*tive\, a. [Cf. F. palliatif.]
   Serving to palliate; serving to extenuate, mitigate, or
   alleviate.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Palliative \Pal"li*a*tive\, n.
   That which palliates; a palliative agent. --Sir W. Scott.
   [1913 Webster]

WordNet (r) 3.0 (2006):

palliative
    adj 1: moderating pain or sorrow by making it easier to bear
           [syn: alleviative, alleviatory, lenitive,
           mitigative, mitigatory, palliative]
    n 1: remedy that alleviates pain without curing [syn:
         palliative, alleviant, alleviator]