Large, beautiful breasts that are keep well consealed and initially appear to be much smaller and less impressive than they actually are until unleashed.

"New Found Friend"

When you go away on holiday or college trip, and one of your friends spends his time ignoring you to speak to other people and trying to be popular.

NFF is a nice way of saying Not Fucking Funny

Not Family Friendly" -- email subject warning code for "Don't look at this in front of the kids -- and use judgement about your significant other

No Fault Found

Technical support term meaning all is well, the end user is to blame.

See also PEBKAC