Least favorite is “bitchin”
My father-in-law is fond of right on - and I want to run screaming from the room every time he says it. He’s a very dear, sweet man, and I know he uses that term thinking he’s very “with it” but I truly wish there was a way to get him to stop. I’ve always hated that phrase.
Todays word for “cool” is, in fact, Zebra.
Try it.
I just found 50 bucks!
That is sooooo Zebra!
I thought that movie was going to be lame but it turned out to be super Zebra man.
You want to get mexican for lunch ? I’m Zebra with that plan.
So remember, Zebra = cool.
Another vote for “spiffy”!
Hmmm … wonder why I like that one!
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Anyway, when I was in high school mumble mumbleyears ago, we used “choi” to mean cool.
Why?
Well, first the cool (there’s that word again!) kids started to use “choice” to mean “cool.”
This caused the kids who wanted to be cooler than cool to adopt a shortened version of “choice” which was of course “choi.”
We were weird …
Zebra
Your post makes me think of “Swingers” and how everything was “money.”
Anybody use “money” in the sense of its usage in that flic?
There is a very good word for “cool” in Russian. It literally translates as “cunty.” Something with a cunt can not be that bad, can it?
For my fellow 20’s slang fan, I also use “aces” when describing something cool.
I keep thinking that the Canadian version of “cool” should be “warm” - warm is the most complimentary word I can think of most of the year.
Favorite: “the tops”
Funniest: “boss”
Dumbest: “da bomb (diggity)”
I regularly use: “cool” and “awesome”
Nostaligic: “tubular” “rad(ical)” and “mint”
My favorite: “keen”
Least favorite: “the shizznit”
Most dated: “tubular”
I propose a new expression for cool:
M.O.C.
It’s just “gangsta” enough to be cool, and of course everybody knows that anything gangsta is cool;) .
“Dude, that set o’ wheels is just M.O.C., yo?”
What does M.O.C. stand for? Nothing, really.
You could come up with:
Most obviously cool
or
Made Outrageous Condition
or
Mighty obvious choice
Dosen’t matter, though.
M.O.C.!!!
Those currently in rotation to answer the question, “How are you?”:
Smashing
Jim Dandy
Used to describe a pretty girl:
Shiny
(As in, “Man, that girl is some kinda shiny!” Alternatively in a plural noun form, “Whoa…check out all the shinies!”)
Minty
(same usage)
Definitely most dated:
Radical, Bodacious (not that I ever hear it, but if I did, it’d be dated), Gnarly, Way Cool (“way” is soooooo last decade)
Most irritating is most definitely, “da bomb”. I have sometimes wondered whether hip, urban-speakers have been pulled aside and cavity-searched at the airport for having what was, to them, a rather innocuous conversation about something that tickles their fancy.
Go to the Visual Thesaurus mentioned in this thread . It is truly frickin cool, smashing, keen, bang-up, corking… 
Has everyone forgotten “slick” My version “slicker than owl shit” is my favorite.
well, i’m kind of amazed that nobody has listed my favorite! i use “sweet” even more than cool! i swear i’ve heard plenty of other people use “sweet” in this type of context. i didn’t just make it up did i?
Nah, I think Cartman from “South Park” started the whole “Sweet” thing. I say it too, didn’t even think about it though.
that’s right!! thanks, GMR! I knew I wasn’t crazy…at least…not for that reason!
I’m still enamoured of ‘cool’ and use it with regularity.
‘dude’ annoys the hell out of me - unless I’m using it. 
‘bummer’ ‘bitchin’ or ‘BAD!’ seem to me to be the most outdated.
Shortest shelf life? Well, a young man maybe no more than 17 or 18 wlked up to me and my motorcycle the other day and, with a big smile and great admiration said “Dude, that bike is SICK!!” I’m not completely out of the loop, working at a Fox station and all, but it took me a moment to remember that this was a complimentary phrase. So, for shortest shelf life, I nominate ‘Sick’
Arrrggghh, “Rumblefish”…GACK!! “The Outsiders”.
I’ve truly dated myself now. But, but, I was just a LITTLE kid when those books came out, they must have still been using “tuff” in CA that’s it!
I really disliked “keen”. I saw it used by a horrendous young actor on the TV show Flipper once: “Gee. Bud. That was. Really. Keen.” and I hated it ever since.
I personal like to use “funky” as my synonym for ‘cool’.
The class of '68 Villa Rica High School sends the following synomym: Tuff! (tough)
As in , “Man, that girl is tuff as nails!”
Thanks
Q