"resembling or of the nature of a squalid district of a city," 1873, from slum (n.) + -y (2). Related: Slummily; slumminess.
Entries linking to slummy
slum n.
"squalid district of a city, low and dangerous neighborhood," 1845, shortened from back slum "dirty back alley of a city, street of poor or low people" (1825), originally a slang or cant word meaning "room," especially "back room" (1812), like most cant words it is of unknown origin. It also meant "nonsensical talk or writing" (1812). Related: slums. Slumscape is from 1947.
-y 2
adjective suffix, "full of or characterized by," from Old English -ig, from Proto-Germanic *-iga- (source also of Dutch, Danish, German -ig, Gothic -egs), from PIE -(i)ko-, adjectival suffix, cognate with elements in Greek -ikos, Latin -icus (see -ic). Originally added to nouns in Old English; used from 13c. with verbs, and by 15c. even with other adjectives (for example crispy). Adjectives such as hugy, vasty are artificial words that exist for the sake of poetical metrics.