1. most characteristic of or resembling a slum; most run-down, overcrowded, or impoverished in appearance
Usage: superlative form of slummy

Examples

• That was the slummiest neighborhood I had ever seen.
• The slummiest part of the city desperately needed urban renewal.
• They lived in the slummiest apartment building on the block.
• The documentary showed the slummiest conditions in the refugee camp.
• Even the slummiest areas of town had some redeeming qualities.
• The slummiest districts often lack basic services like clean water.