So in one game, I was messing around with one person, lying about my army income via exaggeration.

Then in one turn, that player typed in the term "u fr". Soon after, he then ended up surrendering. It was used in a negative context.

... What the heck does "u fr" mean?

Is it something, like "you for real", or "you faggert" (I'm being serious here)?

I'm stuck.

"u fr" could either be a derogatory term for guessing your french nationality, or he had a stroke and hit send by accident, and you're making fun of a dead man :(

In real life it is an acronym for Union Froncophone. Basically he was calling you French, and he doesn't like French people

Undressed fugly redhead.

It's a technical term, actually. He was referring to your exaggerated income

...lying about my army income via exaggeration.

that is so very funny sentenced
I would gladly accept a game with you