Other forms: squalidest
Squalid things appear neglected, or morally repulsive in nature, like a frat house after a semester of hard partying and zero cleanup.
Squalid comes from the Latin word squalere, meaning to “be covered with a rough, scaly layer.” A few word evolutions later and we have squalid, a word that describes something distasteful, dirty, unattractive, and as unkempt in appearance as the dry, scaly skin of an armadillo, or a room filled with pizza boxes, flickering light bulbs, and stained wallpaper. Squalid behavior is dirty, too, like cheating on a test and lying about it.