left to one's own devices, to be

left to one's own devices, to be

To be allowed to do as one pleases; to be left alone. The word devices in this meaning—projects or stratagems— survives mainly in this cliché, which dates from the late nineteenth century. It also appears in a phrase still used from the 1552 Anglican Book of Common Prayer: “We have followed too much the devices and desires of our own hearts.”
See also: left, own