misbehave

from WordNet (r) 3.0 (2006)

misbehave
    v 1: behave badly; "The children misbehaved all morning" [syn:
         {misbehave}, {misconduct}, {misdemean}] [ant: {behave},
         {comport}]

from The Collaborative International Dictionary of English v.0.48

Misbehave \Mis`be*have"\, v. t. & i. [imp. & p. p. {Misbehaved};
   p. pr. & vb. n. {Misbehaving}.]
   To behave ill; to conduct one's self improperly; -- often
   used with a reciprocal pronoun.
   [1913 Webster]