Plain meaning
Start with the shortest useful explanation before going deeper.
A decentralized exchange allowing peer-to-peer token trading without a centralized order book or custodian. Users trade directly from their wallets. DEXs use automated market makers (AMMs) or on-chain order books. Advantages: no KYC, self-custody, censorship-resistant. Disadvantages: potential for higher slippage, smart contract risk, and MEV extraction.