Goody-goody

Good·y-good·y

Goody-goody

a.
  1. Mawkishly or weakly good; exhibiting goodness with silliness. [Colloq.]

goody-goody

n.
  1. A person who is weakly, sentimentally, or affectedly good; a goody-goody person; -- sometimes used to refer to person who acts with good intentions but who bunglingly does more harm than good. The latter may sometimes be deprecatingly referred to as a goo-goo. [Colloq.]