The strange, often concerning behaviour that many people exhibit following a break up with their significant other, and/or in response to the jealousy of seeing them with someone else, in an attempt to cover up how broken they are deep down.
It usually consists of trying to
act happy, and like everything is perfectly
normal, psychologically blind to the fact that they are acting anything but normal.
Named for the behaviour Ross Geller exhibits in the "Friends" episode "The One Where
Ross is
Fine"
"Man,
Matt just broke up with Stephanie yesterday and this morning he invited me to a concert next week and started talking about his plans to become a YouTuber! Is he ok?"
"He will be, man. He's just got
Ross-is-
fine syndrome. Give him some time to grieve"