assentation

from The Collaborative International Dictionary of English v.0.48

Assentation \As`sen*ta"tion\, n. [L. assentatio. See {Assent},
   v.]
   Insincere, flattering, or obsequious assent; hypocritical or
   pretended concurrence.
   [1913 Webster]

         Abject flattery and indiscriminate assentation degrade
         as much as indiscriminate contradiction and noisy
         debate disgust.                          --Ld.
                                                  Chesterfield.
   [1913 Webster]