[ ɪ'nə:ʃə ]
■ noun
1》 a tendency to do nothing or to remain unchanged.
2》 Physics a property of matter by which it continues in its existing state of rest or uniform motion in a straight line, unless changed by an external force.
↘resistance to change in some other physical property: the thermal ~ of the oceans.
Origin
C18: from L., from iners , inert- (see inert ).