1. Some dwelling, accommodation, or other residence that is particularly squalid or decrepit. The first thing I do when I get a better paying job is to get out of this rathole as soon as possible. They stuck me in some crummy little rathole built inside of a warehouse in an industrial park outside of town until the heat from the police died down.

2. Something into which seemingly endless amounts of resources, usually money, can be wasted. Everyone keeps clamoring for a revamped public transit system, but the local government has already thrown nearly half a billion dollars down that rathole with hardly anything to show for it. I just don't see the point in pouring any more time and money into that rathole. Let's just sell it for scrap and cut our losses.

3. A topic, issue, or process that is particularly strange, problematic, difficult, complex, or chaotic, especially one that becomes increasingly so as it develops or unfolds. An uncommon variant of "rabbit hole." Owning your own business is a huge responsibility that not everyone is prepared for. Are you sure you're ready to go down that rathole? Overhauling the current tax legislation is a rathole I don't think this administration should go down at this point.