Related Clues:
- Hard to get through ... or get through to
- Opposite of fluffy, for a cake
- Like osmium and iridium
- In need of a hint
- Baffled by a clue, say
- Not the brightest — studies English!
- Like dumbbells
- Closely crowded; stupid
- Pretty thick
- Initially dim, exhibiting no serious erudition
- Thick poles planted in river
- Retreats before smoke finally becomes impenetrable
- Opposite of sparse
- Like flourless chocolate cake
- Crowded or tightly-packed