...the rest of the class kept shooting furtive glances at him,
Mr. Weasley marched Harry across the short stretch of pavement toward the first of two old-fashioned dark green cars, each of which was driven by a furtive-looking wizard wearing a suit of emerald velvet.
There are no more uses of "furtive" in the book.
Show samples from other sources
She watched me in a furtive manner—trying to hide her interest.
Later she said she was just trying to figure out whose phone it was, but she looked around furtively before she began reading my text messages.