azanul is a Khuzdul word that can mean the adjective "of the shadows, dim", or the while name "Dim-rill"
It is possible that the following is the adjectival ending -ul.
- It can be analyzed as (duban) Azanul-bizar "dim-rill (dale)" or Azan-ûl bizar "dim-rill dale"
 Other versions
Tolkien intended the word Azanûl to be the full name of that valley, but settled on Azanulbizar. The interpretation of the word, as well as that of the bizar have changed. Tolkien experimented with various interpretations of the different elements, though the whole was to somehow express "Dimrill Dale".