obscure

obscure \uhb-SKYOOR\, adjective:

1. not clearly expressed; hard to understand
2. to hide from view; dim, darken
3. not well known; not prominent
4. dark, dim, murky

An obscure federal agency with a history of setbacks announced Thursday that it will upgrade its troubled wastewater treatment plant in San Ysidro.
-- Mike Lee, The San Diego Union-Tribune, 2008-05-18

Either way, it's the sort of obscure Australiana that fascinates local historian David Morgan, who has been an inveterate collector of trivia, compiler of lists and orchestrator of improbable connections since he began thumbing through encyclopedias as a child.
-- John Huxley, The Sydney Morning Herald, 2005-11-12

c 1425, from Old French obscur "dark, dim, not clear," from Latin obscurus "covered over, dark, obscure, indistinct," from ob "over" + -scurus "covered," from Proto Indo-European *(s)keu- "to cover, conceal;" source of Old Norse sky, Old English sceo "cloud," Latin scutum "shield" and Greek skeue "dress.". The verb is first recorded 1475.