Green’s Dictionary of Slang

streaker n.

[originated on US campuses, where it amounted to the trad. mooning (cf. moon n. (1e)), writ much larger, then transferred into a variety of larger arenas, notably the venues of major sporting events around the world]

(orig. US) one who runs naked through a public place.

[US]Time 10 Dec. 14: Streakers generally race nude between two unpredictable points, and the idea is catching on among college students and other groups.
[UK]Guardian Rev. 10 July 12: ‘We have a streaker! No, we have two streakers!’ he cried.
[UK]Indep. Rev. 3 June 4: A streaker on a rugby pitch.
[UK]Observer Mag. 1 May 43/1: We had a streaker once [...] he ran naked through the Music and Junior [library departments].