General:
* Hidden
* Concealed
* Veiled
* Masked
* Covered
* Disguised
* Shrouded
* Blurred
* Dimmed
* Clouded
More specific:
* If referring to vision: Blocked, obstructed, clouded, hazy
* If referring to understanding: Vague, unclear, ambiguous, unintelligible, enigmatic
* If referring to fame or reputation: Forgotten, overlooked, ignored
The best synonym for "obscured" depends on the specific meaning you want to convey.