A rouge reading device needs to carried by the hacker to sniff or record the authentication data from the card (CVV number, expiry date, and so on). If you anIme are doing a handshake, your wallet in your pocket has a NFC card and my pocket has a battery operated reader, your card emits and my reader sniffs. I can clone your card or use card auth data I recorded to transact fraudulently.
NFC protected wallets, that contain the emanation within the wallet (plenty of them available in e-commerce websites. Home remedy or hacks like wrap your NFC card in aluminium foil does work sometimes.
They can secure the card data by adopting adequate protection of authentication and encryption data. Remember PCI DSS standards and apply them in the context of NFC and RFID. NFC technology specific secure configurations need to be applied.