Unaffected means not changed or influenced by something. When a power outage hits your neighborhood but your house stays lit because you have a generator, your home remains unaffected by the blackout. When everyone around you is panicking about a rumor but you stay calm because you know it isn't true, you're unaffected by the chaos.

The word often describes a kind of emotional steadiness or immunity. A confident student might be unaffected by teasing that would bother someone else. A professional athlete stays unaffected by the crowd's booing, focusing entirely on the game. When scientists test a new medicine, they want to know which symptoms are helped and which remain unaffected.

Unaffected can also describe someone whose personality stays genuine and natural despite fame or success. An unaffected person doesn't put on airs or act superior. They remain the same friendly, down-to-earth person whether they're talking to the school custodian or the principal. This kind of person hasn't let circumstances change who they really are.

The opposite is affected, which can mean influenced or changed, or (when describing personality) artificial and pretentious.