As a metaphor for a situation that is out of control or poorly handled, dumpster fire came into prominence in 2016, very frequently in the context of the U.S. presidential campaign. It evokes an image of an uncontrolled blaze in a dumpster, a large trash receptacle that originated as a proprietary name. Dumpster was in commercial use beginning in the 1930s before becoming genericized.
Isn’t that two words?
(Via The American Dialect Society.)