Green’s Dictionary of Slang

scourer n.

also scowrer
[scour v.2 (3); the term was used as the title of the play by Thomas Shadwell, The Scowrers (1691) ‘an excellent but coarse comedy, which gives an interesting picture of the times’ (DNB)]

[17C–18C] (UK Und.) a dissolute young man who roams the streets, usu. as one of a gang, beating up passers-by, breaking windows, attacking the watch and generally acting in a hooligan manner.