This is a handmade dress with the most vibrant colors in a wild pattern of peacock feather.  The fabric appears to be synthetic and the colors are so bright: florescent orange, green, red, fuchsia, black, magenta and bright blue.  

The selvage on the sleeve is stamped: "copyright: VHY Hawaiian Textiles #7188".  I looked it up and found that this fabric was printed in the 1950s/60s.  

The style is a simple "shift" dress and it would be great for a Halloween costume or for everyday wear. 

Since there is no label, please use the measurements below to figure out the size.  If I had to guess I would say size 10.