1.
sleepyhead; late riser; slugabed
A person who oversleeps or has difficulty waking up. Used affectionately or teasingly, especially toward children or close friends.
My little brother is a sleepyhead and gets woken up by our mother every morning.
Compound of 寝坊 (oversleeping) + すけ (a suffix used to characterize a person, often with a playful or teasing tone). The same suffix, written 助, appears in other teasing labels such as 飲み助 (heavy drinker) and ちび助 (little one).
Common collocations
Register
Mostly informal and affectionate. Commonly used by parents addressing children or among close friends. Not used in formal or business contexts.