I wouldn’t consider this group euphemisms at all. Firearm is the generic for pistol/rifle
type weapons. Properly speaking, at least in military parlance, ‘guns’ are the big-barreled
things. Firearms are (small) arms which shoot projectiles using fire (gunpowder)…
‘Saturday Night Special’ is a nice euphemistic nickname for cheap short-barreled hold-up
weapon. ‘Piece’ is also nicely euphemistic in this area, and as a pun, interestingly ironic as
well.
Substance abuse is just shorter than mind-altering substance abuse and less technical (and specific) than Misuse of a Class C Substance. Also more generic, and manages to catch
alcohol abuse and ‘drug’ abuse in the same category. There aren’t too many good
euphemisms in this area, though ‘a bit fond of the bottle’ is a pleasant way to describe an
alcoholic. Somehow ‘a bit fond of the needle’ doesn’t have the some comforting ring…
A psychiatric hospital is … a hospital for people with psychiatric problems. It’s not
perjorative like ‘looney bin’, but it’s not euphemistic like ‘retreat’, ‘park’, or ‘home’. …
and they are hopefully fundamentally different from ‘insane asylums’ in maybe being a
place of treatment and not just isolation.
Actually, for the longest time we had ‘state schools’ here, which actually were insane
asylums in all practical senses. The only conceivable reason to call them ‘schools’ is too
make them sound safer and gentler. They weren’t really schools in any sense. That was
a beautifully political euphemism.
Shell shock is specifically combat fatigue caused by the disorientation of not knowing where a shell is going to land. Combat fatigue is a pretty accurate description of what happens - the mind gets exhausted from constant alertness to potential death and starts going haywire.
Post-traumatic stress disorder is the technical and generic term for people who… suffer stress… after experiencing a trauma of some kind. (I have trouble conceiving of anything
with the word ‘trauma’ in it as a euphemism. ‘Trauma’ is the category that contains things
like gut-wounds from butchers knives, near-fatal shootings, and the aftermath of being
launched through a car window when you weren’t wearing your seatbelt…)
Swearing, or profaning is things like using a diety’s name in vain, Cursing is things like damning someone, and vulgarity is using anglo-saxon language in the description of bodily functions and parts that are sexual or eliminatory in nature. And then there’s racial epithets, and so on, as well. ‘Improper Language’ covers the whole lot rather succinctly. ‘Bad language’ or ‘bad words’ might be as succinct and a little more plain.
Now, saying that someone is ‘plain spoken’ when you mean they are constantly swearing
and using vulgarity, that would be a fine euphemism. Alas, nobody would understand
the proper meaning, as plain spoken has come to mean speaking forthrightly. The slightly
less euphemistic, but still primly proper, ‘coarsely spoken’ might still be understood though.
‘Economic downturn’ … isn’t even a euphemism… it’s a plain old understatement, in
reference to recent years… an economic downturn is when the economy slips. A
recession is when the economy slips for awhile. A depression is when the economy
slips for quite awhile and lots of people lose jobs. We’re just now coming out of a
depression by pre-dot-com economic measures, but the definition of depression was
rapidly redefined when Bush took office. I’m not sure what kind of phrase ‘jobless
recovery’ is, though ‘ludicrous’ and ‘ridiculous’ come to mind…
Ahhh, another fine stream of babble. I hope you enjoyed. Or at least won’t lynch me. 
–Chris
