Can someone use my internet without knowing my password

Yes, it is possible for someone to use your internet without knowing your password, although modern security measures make this less common if proper precautions are taken.

Unsecured Network: If your Wi-Fi network has no password protection, anyone within range can easily connect to it.

Giving out your password: Sharing your Wi-Fi password gives guests full access to your local network, creating risks like data exposure, bandwidth hogging, and potential malware spread.

Hacking/Cracking the Password: Attackers with advanced skills and specific tools can attempt to crack weak passwords, although modern WPA2 and WPA3 encryption makes this difficult if a strong, unique password (a "passphrase") is used.

Malware: If a device already connected to your network is infected with malware, an attacker might gain remote access to your network through that compromised device.

Physical Access: Someone with physical access to your router can easily connect a device via an Ethernet cable or use the WPS button, bypassing the need to know the wireless password.