| Slow |
| Dull |
| Dumb |
| Firm |
| Solid |
| Thick |
| Foggy |
| Stupid |
| Packed |
| Obtuse |
| Jammed |
| Opaque |
| Complex |
| Crowded |
| Compact |
| Crammed |
| Doltish |
| Serried |
| Thickset |
| Blockish |
| Populous |
| Close ... |
| Dimwitted |
| Compacted |
| Overgrown |
| Jam-packed |
| Not bright |
| Meatheaded |
| Very thick |
| Not sparse |
| Crammed in |
| Compressed |
| Thickheaded |
| Slow-witted |
| Thick crowd |
| Impenetrable |
| Concentrated |
| Bubbleheaded |
| Needs (anag) |
| Thick headed |
| Very compact |
| Like a copse |
| Packed tight |
| Close-packed |
| Like mercury |
| Blockheaded. |
| Knuckleheaded |
| Unintelligent |
| Bubble-headed |
| Not too sharp |
| Not too smart |
| Chuckleheaded |
| Hardly sparse |
| Like platinum |
| Firmly packed |
| Like thickets |
| Cement-headed |
| Not too swift |
| Heavy, as fog |
| Thick, as fog |
| Like some fog |
| Sold-out show |
| Tightly packed |
| None too smart |
| Not too bright |
| Not very sharp |
| Not getting it |
| Like a thicket |
| Dumb as a rock |
| Like thick fog |
| None too swift |
| Like heavy fog |
| Packed tightly |
| Closely packed |
| Not too astute |
| Thickly packed |
| Not very bright |
| None too brainy |
| Heavy, as a fog |
| Highly populous |
| Scarcely bright |
| Thick, like fog |
| Like a dumbbell |
| Packed in tight |
| None too bright |
| Not at all sharp |
| Incredibly thick |
| Like a numbskull |
| Like dunderheads |
| Slow to catch on |
| Like a blockhead |
| Crowded together |
| Thick as a brick |
| Crowd at big show |
| Like a black hole |
| Really crammed in |
| Rearranged needs? |
| Thick — compact |
| Like some forests |
| Hard to penetrate |
| Like pea-soup fog |
| Thickly populated |
| Slow on the uptake |
| Needs another way? |
| Short on sharpness |
| Tightly compressed |
| Not Mensa material |
| Slow to understand |
| No rocket scientist |
| Like a neutron star |
| Like thick audience |
| Hard to get through |
| Like a pea-soup fog |
| Highly concentrated |
| Hard to see through |
| Tough to get through |
| Like depleted uranium |
| Like some populations |
| Thick, like heavy fog |
| Unable to get it, say |
| Like urban population |
| Like crowd at big show |
| Like sold-out audience |
| Dumb as a box of rocks |
| Like urban populations |
| Hard to get through to |
| Packed closely together |
| Sharp as a bowling ball |
| Hardly suited for Mensa |
| Like Archie's pal Moose |
| Obtuse — impenetrable |
| Tough to get through to |
| Difficult to get through |
| Like sold-out show crowd |
| Practically impenetrable |
| Closely crowded together |
| A little on the slow side |
| Thick in a couple of ways |
| Like Jupiter's atmosphere |
| A few bricks shy of a load |
| A few bits short of a byte |
| Compact and tight together |
| Not so swift on the uptake |
| Not exactly Mensa material |
| A little slow on the uptake |
| Hard to hack a path through |
| Hard to see through, as fog |
| Not too quick on the uptake |
| Heavy, like some baked goods |
| None too quick on the uptake |
| A few players short of a team |
| Guolaugur Ottarsson: "___ Time |
| Having a high specific gravity |
| Packed with ideas, as an essay |
| One burrito shy of a combo plate |
| With a high mass-to-volume ratio |
| A few fries short of a Happy Meal |
| Not the sharpest tool in the shed |
| Like crowd during sold-out concert |
| Not the sharpest pencil in the box |
| Not the brightest bulb on the tree |
| Hardly qualified to be a rocket scientist |
| Not the brightest bulb on the Christmas tree |
| Like osmium, more than any other known element |