Source : Webster's Revised Unabridged Dictionary (1913)

Expostulation \Ex*pos`tu*la"tion\, n. [L. expostulatio.]
   The act of expostulating or reasoning with a person in
   opposition to some impropriety of conduct; remonstrance;
   earnest and kindly protest; dissuasion.

         We must use expostulation kindly.        --Shak.

Source : WordNet®

expostulation
     n 1: the act of expressing earnest opposition or protest [syn: {remonstrance},
           {objection}]
     2: an exclamation of protest or remonstrance or reproof