Questions & Answers about Claritatea este importantă.
Because Romanian usually puts the definite article at the end of the noun, not before it.
- claritate = clarity
- claritatea = the clarity
So -a here is the feminine singular definite article attached to the noun.
Romanian often uses the definite form with abstract nouns when speaking in a general way.
So even though claritatea literally looks like the clarity, the sentence is naturally understood as a general statement, like English clarity is important.
This is normal Romanian usage, not something unusual about this sentence.