They were speaking low and furtively, but they were near, and coming nearer.
Out of the shadows the hobbits peeped, gazing back down the slope: little furtive figures that in the dim light looked like elf-children in the deeps of time peering out of the Wild Wood in wonder at their first Dawn.
But make haste! Be silent! ’ As furtively as scouts within the campment of their enemies, they crept down on to the road, and stole along its westward edge under the stony bank, grey as the stones themselves, and soft-footed as hunting cats.
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.