Keylogger
Malicious software or hardware that secretly records every keystroke a user types, often to steal passwords.
A keylogger↗ is malicious software, or occasionally a physical hardware device, that secretly records every keystroke a user types, often without any visible sign that it's running. Attackers use keyloggers specifically to capture passwords, credit card numbers, private messages, and other sensitive information as it's typed.
Keyloggers are usually installed through malware↗ delivered via phishing↗ emails, infected downloads, or compromised software, and they typically send the captured data back to the attacker over the internet. Reputable antivirus↗ software, being cautious about what you install, and using a password manager↗ (which fills in passwords without you typing them) all help reduce the risk of falling victim to one.