Warehouse jumpsuit play suit.   Size label S but being stretchy I would say it fits a size 12 better or even a size 14.

I wore this to a tropical 1940s Hawaiian event with hula garlands.  It was very fetching and comfortable.  Pullover closure, no zips, buttons.  Wide-leg trousers.  Elastane and polyester blend.  Easy to wear.  Multicoloured fabric.  IT IS NOT AN ORIGINAL 1940s or 1950s JUMPSUIT.