inertial
noun(in-er-tia)
a property of matter by which it remains at rest or in uniform motion in the same straight line unless acted upon by some external force
inertial
noun(in-er-tia)
an analogous property of other physical quantities (such as electricity)
inertial
noun(in-er-tia)
indisposition to motion, exertion, or change : inertness
inertial
noun(in-er-tia)
guidance (as of an aircraft or spacecraft) by means of self-contained automatically controlling devices that respond to inertial forces —called also inertial navigation