Etymology

Adjective

1. taking place
2. trendy, up-to-the-minute

   He is a real happening guy.

3. A term that became popular during the middle-to-late 1960s to denote an event with multiple cultural components, such as a graphic arts exhibition with accompanying or associated contemporaneous musical, social, and political events.

   The Andy Warhol reception was a freaky happening.

Noun

1. something that happens
2. a spontaneous or improvised event, especially one that involves audience participation