Ástæðan er enn ekki skýr.

to be

Breakdown of Ástæðan er enn ekki skýr.

• ekki: not
• skýr: clear
• enn: still

Questions & Answers about Ástæðan er enn ekki skýr.

Why is it ástæðan instead of ástæða?

Because -n is the suffixed definite article. So:

• ástæða = reason
• ástæðan = the reason

Icelandic usually adds the to the end of the noun instead of using a separate word like English does.

What case is ástæðan in here?

It is nominative singular. It is the subject of the sentence, so nominative is the expected case.

A useful contrast:

• ástæðan = nominative, the reason
• ástæðuna = accusative, the reason as a direct object

Why is er used here?

er is the present-tense singular form of vera, which means to be.

So the structure is simply:

• Ástæðan = the reason
• er = is
• enn ekki skýr = still not clear

Why is er in second position?