Email spoofing is covered in the entry Spoofing, which explains the different forms of impersonation used in fraud and how organizations defend against them. This page gives a short definition and explains how email spoofing fits in.
Email spoofing is the forging of an email's sender information, most often the "From" address and display name, so that a message appears to come from a bank, a supplier, a colleague or a crypto exchange when it does not. It works because the basic email protocol was designed without built-in checks on who the sender is. Spoofed emails are a mainstay of phishing, in which recipients are lured into clicking links or entering passwords, and of business email compromise, in which staff are tricked into paying fake invoices or changing bank details. They are a form of social engineering. Email providers and companies counter them with authentication standards known as SPF, DKIM and DMARC, which let receiving servers check whether a message really came from the domain it claims, while users are advised to verify unexpected payment requests through a separate channel and to be wary of identity theft attempts.
Spoofing can also target phone numbers, websites, text messages and, in markets, order books. Email spoofing is simply the most common form, so this site covers it within the main entry.