(V;): fat shaming is the act of poking fun of someone for being overweight, or telling someone they are worthless, useless, lazy, or disgusting because they are overweight.
Like most terms, this has been adoptwisted by Radical Neofeminists to mean something very different. Under the RNF definition, it means " to make an overweight female feel in any way uncomfortable, usually by telling her anything is wrong with her weight."
This unfortunately includes Doctors telling them to lose weight for their health and suggesting diets or friends saying that their clothes are too tight, even men very politely refusing dates because they just don't find them attractive.
TRUE DEF. VERSION
Mark: ew lol that girl is disgusting hey fatty your fucking ugly lay off the burgers
Dan: Mark, for fucks sake, stop with the fat shaming already, you're fat too.
RNF DEF. VERSION
Doctor Reid: ma'am, it would do you a world of good to lose around 30 pounds. You're in danger of diabetes at this weight, but with proper diet and exercise we can-
RNF Patient: OMG STOP FAT SHAMING ME MY BODY IS BEAUTIFUL YOU JUST CANT SEE IT BECAUSE YOURE PART OF THE SKINNY PATRIARCHY MODELS ARE TOTALLY UNHEALTHY
Doctor Reid: okay, I'm going to just stick a note in your file that says "uncooperative and delusional" and send you up to the psych ward, alright?