Noun inertia has 2 senses
  1. inactiveness, inactivity, inertia - a disposition to remain inactive or inert; "he had to overcome his inertia and get back to work"
    --1 is a kind of trait
    --1 has particulars:
     languor, lethargy, sluggishness, phlegm; restfulness; passivity, passiveness; indolence, laziness
  2. inertia - (physics) the tendency of a body to maintain is state of rest or uniform motion unless acted upon by an external force
    --2 is a kind of
    mechanical phenomenon
    --2 has particulars: moment of inertia