freewheel

A device in a transmission that disengages the driveshaft from the driven shaft when the driven shaft rotates faster than the driveshaft.

The mode or state of operation thus produced: Synonym of neutral.

To continue spinning after disengagement.

To ride a bicycle without pedalling, e.g. downhill.

On her elderly bicycle with the basketwork carrier on the handle-bars, Dorothy free-wheeled down the hill, doing mental arithmetic with three pounds nineteen and fourpence--her entire stock of money until next quarter-day.

To operate a motor vehicle which is coasting without power, e.g. downhill.

Silently and gracefully I free-wheeled across the path of three juggernauts, [...] glided across the hard shoulder and came to rest halfway up a grass bank.

To operate free from constraints.