sophist
(SOF-ist)
MEANING:
noun: One who makes clever, but unsound arguments.
ETYMOLOGY:
From Latin sophista, from Greek sophistes (sage), from sophos (clever). Earliest documented use: 1542. In ancient Greece, Sophists were philosophers and teachers known for their subtle, but fallacious reasoning.
USAGE:
"But this day Mansoor had turned five, and Ma used a sophist's argument to call for a celebration."
M.G. Vassanji; The Assassin's Song; Doubleday; 2007.

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SOPHISTA- a sophist with latinate pretensions.