Related Clues:
- Unable to get it, say
- Rather unlikely
- Thick; stupid
- Packed tightly
- Impenetrable studies before end of course
- Subdued, as shades
- Like urban population
- One burrito shy of a combo plate
- Compact; stupid
- Like a faint light
- Like a pea-soup fog
- Slow old coach takes time heading east
- Difficult to get through
- Like a low-watt bulb
- Not exactly Mensa material