Your Company is receiving false and abusive e-mails from the e-mail address of your partner company. When you complain, the partner company tells you that they have never sent any such e-mails…

Cyber squatting is the bad-faith registration of domain names resembling trademarks or brand names to profit from them, which is unrelated to forging the sender address of an email message.

Cyber stalking refers to the use of digital means to repeatedly harass or threaten a specific individual, which describes intent and behavior rather than the technical act of forging a sender identity.

Spoofing is the technique of falsifying identifying information - in this case the email 'From' header - so that messages appear to come from a party that did not actually send them. The SMTP protocol historically lacks built-in sender verification, making email address forgery straightforward for attackers. The partner company's denial confirms the address was forged rather than their account being compromised and used to send mail.

A man-in-the-middle attack involves an adversary secretly intercepting and potentially altering communications between two parties in real time, which is a different attack vector from simply forging an email's originating address.