in·side out • adv. with the inner surface turned outward: we made a very quick change, and her dress was put on inside out.• adj. in such a condition: inside-out clothes.PHRASES: know something inside out know something very thoroughly: managers who know the business inside out.turn something inside out turn the inner surface of something outward: she played with her leather gloves, turning each finger inside out. ∎ change something utterly: it is not so easy to turn your whole life inside out. ∎ inf. cause utter confusion in; defeat totally: he turned the defender inside out.