The word "crummy" is an adjective that means something is unpleasant, poor-quality or bad. It can be used to describe a person, place, thing or situation that is not good or enjoyable in some way. For example, you could say "this food tastes really crummy," meaning it doesn't taste very good, or "this hotel room is so small and crummy" indicating that the room is of poor quality. The word can also be used as an exclamation to express disgust or disapproval, for example: "This weather is just so crummy!"