A homograph attack is a spoofing technique that uses characters from different writing systems, or lookalike letter variants, to make a fake name resemble a trusted one. For example, attackers may mix Cyrillic, Greek, or accented characters with Latin letters so a domain, email address, or app name looks legitimate at a glance.
This matters because security decisions often start with what users can see. If a browser, mail client, or chat app renders the deceptive text as readable Unicode instead of a more obvious encoded form such as Punycode, the visual warning signs may disappear. Homograph attacks are common in phishing, brand impersonation, and fake login pages. Defenses include browser and platform policies for displaying internationalized names, domain monitoring for lookalikes, allowlists for high-risk workflows, and user training that treats visual similarity as suspicious rather than proof of trust.