lost motion

noun Machinery.
  1. motion of a machine or mechanism, especially a reciprocating one, during which no useful work is performed.
  2. motion between parts in an assembly due to manufacturing tolerances, adjustments, slip, or wear.

Origin of lost motion

First recorded in 1875–80
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018