transitive verb
1. : to reverse the direction of rotation of (a spindle) for a few turns in mule spinning so that the yarn between the nose of the cop and the point of the spindle may be uncoiled
2.
a. : to remove metal from the back of (a cutting tool) to provide clearance from the work (as in cutting a screw thread)
b. : to remove (as part of a well casing) by unscrewing
3. : to cut away or relieve on the back
back off a cutter or drill to make a clearance
intransitive verb
: to back down or back out