noun
night person; night owl
Describes someone who is naturally more active or alert at night. Often contrasted with 朝型人間 (morning person).
See also: 朝型人間
私は夜型人間で、朝はなかなか起きられない。
I'm a night person and can't easily get up in the morning.
夜
Being a night owl, he likes to work late at night.