An excellent performance. / Someone or something whose performance is excellent. / (sometimes sarcastically) Someone or something who is generally well-mannered, conscientious, etc.

Not of the elite, of the peasantry or working-class. / Unrefined.

(idiomatic) A student who frequently makes jokes or pokes fun; a wiseacre.

(role-playing games) One of a number of pre-determined groups into which characters in role-playing games are grouped, based on the focus of their skills.

(software engineering) A type of static structure diagram that describes the structure of a system by showing the system's classes, their attributes, and the relationships between the classes.

(linguistics) A linguistic form class whose members are words.

(US, colloquial) An introductory university course that is designed to "weed out" those students who are not able to pass it.

(mathematics, topology, geometry) Any of a group of characteristic classes associated with complex vector bundles, with applications in physics, string theory, etc.

(object-oriented programming) Synonym of subclass

(object-oriented programming) An inner class declared outside a function (hence a "member") and not declared as static.