Slugabed is a noun for a person who stays in bed longer than they should, especially in the morning. It usually sounds playful, old fashioned, or mildly critical, rather than seriously insulting.
You most often use it for a person, as in: “Get up, you little slugabed.” In modern English, this use is much more common than any other.
Sometimes the word is also used more loosely for the habit or behavior of staying in bed late, but that is less common. For example, someone might jokingly refer to a lazy morning as a bit of slugabed behavior.
A few helpful points:
- Part of speech: usually a noun
- Meaning: a late riser, especially a lazy one
- Tone: teasing, humorous, or gently disapproving
- Style: somewhat old fashioned, but still understandable
Compare it with early bird, which suggests the opposite habit. If someone sleeps late and avoids getting up, slugabed fits. If they wake up early and eagerly start the day, early bird is the better choice.