Unctuous

Read as \UHNGK-choo-uhs\ and is characterized by excessive piousness or moralistic fervor, esp. in an affected manner; excessively smooth, suave, or smug. Or something that is oily or greasy.

Unctuous and oleaginous are synonymous words that I encountered at Queendom.com, a site for different kinds of tests like IQ test. I didn't know these words before though my partner, who I often called as my walking dictionary, knows them. The word oleaginous is already familiar to me that I chose unctuous to be included in Logofanum so I would always remember it for there is oleaginous in my memory to associate it with.

dictionary.com page link for unctuous