2. Someone you don't really care about is talking to you and they something semi-interesting but not interesting enough for you to care but you don't want to hurt their feelings so you just go "oh, fr?" with ur tone in voice going slightly up.
A: "Did you know that Sasha got in trouble by Ms. Peters today?"
B: "Oh, fr? Why?"
A: "Apparently Sasha had a one-night stand with Ms. Peter's husband! They're going to get divorced now!"
B: "Oh fr? WAIT, FR?"
Commonly used as an abbreviated way to say "for real".
Usually used in texting, as many people use as many abbreviations as possible.
It can be a form of agreement towards someone, or disbelief.
If you use it as disbelief you may put a question mark to emphasize that you're asking if they're being serious.