He had dropped his unctuous tone and his smile now.
"I have, sir," he said, and although his voice was very scared, Harry could still hear the familiar unctuous note in it.
Karkaroff had a fruity, unctuous voice; when he stepped into the light pouring from the front doors of the castle they saw that he was tall and thin like Dumbledore, but his white hair was short, and his goatee (finishing in a small curl) did not entirely hide his rather weak chin.
"Mr. Crouch…. Mr. Bagman," said Karkaroff, his voice unctuous once more, "you are our — er — objective judges.
There are no more uses of "unctuous" in the book.
Show samples from other sources
But she kept her attention on me, unctuously gesturing, and even as he leaned and bucked into her she held out her open hand to me, as if I should take it when I crept my way inside.
Chang-rae Lee -- A Gesture Life
He made no effort to be civil, or his normal unctuous, ingratiating self.