ETYMOLOGY
from omni- combining form of Latin omnis (all) + nescient from Latin nescientem,
pres. pple. of nescire (to be ignorant), from ne (not) + scire (to know)
EXAMPLE
“… The appeal is generally from those who know something to those who know less – and at last to those who are omni-nescient. …”
From: A Report of Proceedings at a Public Meeting of the Merchants, Bankers, and Traders of the City of London, held at the London Tavern, on Wednesday, Dec. 3, 1851
For a Reform of the Board of Customs
Part II. Chapter II. Appeals
Lexicophilia 