The phrase "slab sides" refers to a car that has flat, straight sides without any curves or indentations. It means that the car's body is simple and lacks fancy designs or shapes.
Sentences with «slab sides»
It's an unconventional cabin this, with more curves dominating the proceedings instead of slab side practicality. (carwale.com)
The near slab sided fascia and the rounded AC vents look odd. (cardekho.com)