Green’s Dictionary of Slang

1. a servant girl.

1890–1904

Farmer & Henley Sl. and Its Analogues.

2. a slum-dweller.

1935		(con. 1920s) McArthur & Long No Mean City 11: She was not a real Gorbals ‘slummy’.
1973		(con. mid-1960s) J. Patrick Glasgow Gang Observed 111: Big Fry [...] rose up and tauntingly called out: ‘We’re the slummies!’.

3. an ill-dressed, unattractive woman.

1983

R. Klein Jailhouse Jargon and Street Sl. [unpub. ms.].