Squalid
Etymology
From Latin "squalidus" ("dirty, rough, coarse"), from "squalere" ("to be filthy or encrusted," originally "to be covered in scales"). The underlying image is of grime caked over a surface, which gives the modern sense of foul, neglected filth.
adjective · /SKWOL-id/
Extremely dirty, run-down, and wretched, especially through poverty or neglect.
What it names
The word for grim, filthy conditions unfit to live in — cramped, unwashed, and miserable.
Example
The refugees were crowded into squalid tents with no clean water.
Related idea
Sordid can mean physically filthy but usually means morally degraded; squalid stays focused on filth and wretched living conditions.