NFR is short for Not For Resale.
If you have an NFR license, you likely received it for free from us so you can test, review or demonstrate a certain product, or for any other previously agreed-upon purpose. You may use an NFR license just like a regular license - but you can not sell or transfer it, nor otherwise pass it on to someone else.
An NFR license remains your license forever, or until we decide to revoke it. (Which we usually won’t do, unless we have a really good reason to.)