The Collaborative International Dictionary of English v.0.48:

Admonishment \Ad*mon"ish*ment\ (-ment), n. [Cf. OF.
   amonestement, admonestement.]
   Admonition. [R.] --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

admonishment
    n 1: a firm rebuke [syn: admonition, admonishment,
         monition]