Addiction
Etymology
From Latin "addictio," a formal awarding or handing-over. In Roman law it named a debtor bound in service to a creditor by a judge’s decree — from "ad-" (to) and "dicere" (to say, adjudge). The word’s core image is being given over, bound, to something.
noun · /uh-DIK-shun/
A compulsive drive to use a substance or repeat a behavior despite clear harm.
What it names
Use it for the loss of control itself — the "despite the cost" quality — not mere heavy use or physical need.
Example
What marked it as an addiction was that he kept gambling even after it cost him the house.
Related idea
People conflate addiction with dependence, but they can occur apart: a patient can be physically dependent on a medicine — suffering withdrawal if it stops — without the compulsive, harmful pursuit that defines addiction. Addiction is behavioral loss of control; dependence is a physiological adaptation.