goody-goody /ˌgʊdiˈgʊdi/
  Good·y-good·y, a. Mawkishly or weakly good; exhibiting goodness with silliness. [Colloq.]
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  goody-goody
       adj : affectedly or smugly good or self-righteous
       n : a person who behaves extremely well in order to please a
           superior