Senior, elder, or upperclassmen. Used in cases where the subject is a superior within the same social class.

(also: sempai): upperclassman (ie. Kuno-senpai)

a social elder. The term is usually used in work or at school; the senpai is opposite to kouhai. Mamoru is Asanuma's senpai, because Mamoru is a more senior student at their school.

Suffix used towards an elder/senior/older student.

An honorific used by a young person when talking to or about a benefactor or senior in a social organization. The usage of this honorific is encountered time and again in anime, mostly when students are talking to or about their senior classmates, as in "Tamiya-sempai heads the campus motorcycle club." Used as a noun, it would just mean, "our seniors", or "our upperclassmen".

Japanese term (sometimes an honorific) for a person in a club or other organization, including a school or college, who is a senior (in other words, a member for longer or of a higher year) and mutually recognized as such. The junior counterpart is called . Senpai is often seen romanized as sempai, in accordance with the initial version of the Hepburn romanization system.