I’m a woman, and refer to myself as either “fat” or “overweight.” I don’t care for euphemisms. I shy away from “big” because I’m only 5’3. I would use “fat” more often, but because it has such negative connotations most people think I’m putting myself down vs simply stating a fact. My typical self-description is “short, overweight brunette.” 
And yes, many people feel that it’s OK to randomly comment on a stranger’s weight…either maliciously, or “helpfully.”
Heh, I cheerfully call myself fat. (Also hideous, slovenly, and doomed to die alone.) However if anybody else called me fat (using that term) I’d immediately and correctly recognize them as a worthless dirtbag. There are some things you should say even if they’re true.
If you knew anything about dictionaries, you would know that some are asinine enough to cheerfully include any mistake that happens to be reasonably common.
American Heritage and Collins
If you knew anything about dictionaries, you would know that once a word becomes reasonably common then it’s asinine to exclude it, regardless of if you consider it a “mistake” or not. Dictionaries reflect the language. Language doesn’t reflect the dictionary.
Enjoy,
Steven
In my job, I regularly have to inquire about peoples’ weight, as well as whether it changed recently. I generally ask something like, “So, have you always been a large woman/man?” To date, none of the large people have indicated any offense at all.
Why couldn’t you just say “has your weight changed recently?”?
I was shooting pool in a bar 30 years ago and, as I was taking a shot, heard some guy watching call me “fatass.” I turned around and looked him straight in the eyes, pool cure in hand and said, “What did you call me? You’d better not *ever *call me that again.” And probably some other choice words thrown in. I was pissed off. I guess I looked angry and possibly drunk enough that he apologized profusely more than once then and again later that night. When the, “Is it ok to tell a woman you don’t know that she has hairy arms?” thread comes along I have a story for that, too.
Undertall? Overly horizontal?
How I wish all parents would stop fat-shaming their children. I stopped speaking to my dad for long periods of time as an adult for fat-shaming (and I wasn’t at all overweight then) and finally broke him of the habit. Oddly, he has always been overweight. You’d think he’d know better.
Thick
Referring to people by their size is inappropriate. This is why I dislike when basketball players are referred to as ‘bigs’ and ‘smalls’.