mua trâu vẽ bóng 
buy a pig in a poke [ mua ] : to buy, purchase, get
[ trâu ] : buffalo
[ vẽ ] : drawing, sketch; to draw, paint, sketch
[ bóng ] : (1) balloon, ball; (2) shadow, shade, light, photograph; (3) shiny
Most Common Compounds Set 1:
Most Common Compounds Set 2 :