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Refers to something that an individual would deem widely accepted or cool to show off, but in reality it just makes them look like a fucking idiot/weird.
Example 1:

Person 1: Strawberries on Pizza are to die for.
Person 2: This ain’t it Chief.

Example 2:

Person 1: Who’s excited for the new Teen Titans GO Movie??
Person 2: This ain’t it Chief.
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