1
final coat (of paint, plaster, varnish, etc.);finish;glazing
彼は壁にペンキの上塗りをした。
He put the final coat of paint on the wall.
2
adding more of the same (of something negative, e.g. shame)
See also:
恥の上塗り (はじのうわぬり)
Other forms
上塗 【うわぬり】