| Thickest |
| Stupidest |
| Most stupid |
| Most obtuse |
| Least bright |
| Least clever |
| Least sparse |
| Most crowded |
| Most compact |
| Most mindless |
| Most populous |
| Most intense. |
| Most populated |
| Most slow-witted |
| Most thickheaded |
| Most thick, as fog |
| Most tightly packed |
| Hardest to penetrate |
| Hardest to comprehend |
| Slowest on the uptake |
| Obtuse in the extreme |
| Hardest to get through |
| Least likely to get it |
| Most thickly populated |
| Least likely to understand |