Might be an age thing. I was in my single digits to early teens then, and it was old fogey slang to us before coming back. It was something I associated with — I dunno — hippie and maybe jazz slang? 70s blacksploitation films? Like there was that 80s standard, “Hip to be Square,” which I always assumed was ironic in its use of both “hip” and “square” as outdated, uncool slang. Speaking of jazz slang, I can use words like “cat” as in “hip/hep cat” without feeling ironic now, too. At least among people my age. But that may be pushing it a bit. (I tend to only use that around musicians.)
Very interesting how adjectives can shift meanings like that. It’s not slang, but it reminds me of the word ‘sophisticated’ for some reason, which today is very positive, meaning worldly and refined; but used to be very negative, meaning dishonest, manipulative or misleading.
Correction: It was in his book Nine Nasty Words.
It goes back a lot further that that.
From Michael Ventura’s extraordinary essay “Hear That Long Snake Moan” (PDF link), about the history of rock and jazz music:
… the use of the concept “cool” among the Yoruba people of Africa is precisely the same as its use as popularized by jazz musicians in New York [seventy] years ago – another usage that’s remained constant with us. Said one Yoruba informant to Thompson, “Coolness is the correct way you represent yourself to a human being.”
In his remarkable book Flash of the Spirit Thompson writes:Like character, coolness ought to be internalized as a governing principle for a person to merit the high praise, “His heart is cool” (okan e tutu)… So heavily charged is this concept with ideas of beauty and correctness that a fine carnelian bead or a passage of exciting drumming may be praised as “cool.”
Coolness, then, is a part of character… To the degree that we live generously and discreetly, exhibiting grace under pressure, our appearance and our acts gradually assume virtual royal power. As we become noble, fully realizing the spark of creative goodness God endowed us with… we find the confidence to cope with all kinds of situations… This is character. This is mystic coolness…
Coolness doesn’t mean coldness. Cool art is passionate art. In American culture, Miles Davis has been the exemplar of this aesthetic. When in 1949 and 1950 he was making the recordings – with, it should be noted, white musicians like Gerry Mulligan, Lee Konitz, Gunther Schuller and Gil Evans, as well as blacks like J.J. Johnson, John Lewis, Kenny Clarke and Max Roach – Davis would call those sessions “birth of the cool.” But those sessions might better have been called “rebirth of the cool.” They were, in music, a restatement of… African philosophy in American terms. That has been the life of all Miles Davis’s music, and he himself has been absolutely sure of this.
Interesting how this thread has immediately and almost entirely converged on a discussion of “cool”. Back in the mid-1960s anyone who wasn’t cool was likely to be called a spazz.
One thing I clearly remember about “spazz” was that there was active discussion and debate about how to spell it.
Zounds! Gadzooks, I say! Odds bobkins, even!
At some point in the last 10 years or so, I was also surprised to hear “sucks” used in mixed company (around kids and older people, and yeah, I’ve heard it in a sitcom). Back in my day, it bordered on profanity. But I recall reading somewhere, maybe here at the SDMB, that it goes way back, coming from the expression “sucks eggs,” which might characterize a rube. Even if that’s true, I doubt anyone is thinking that when they say it today.
I enjoy weather idioms describing rain:
It’s raining cats and dogs.
A gulley washer.
A frog strangler.
It’s raining buckets.
“Cool” is all in how you say it. Let’s ask an expert:
“Radical” is certainly dead, but within the last week I heard a mid-to-late 20s Twitch streamer react to something by saying, “Wow, that looks rad.” And it wasn’t the first time, either.
It may not be terribly common, but it’s definitely still hanging on.
“Man whats the matter with that cat there?”
“Must be full of reefer”
“Full of reefer?!”
“Yea man”
“You mean that cats high?!”
“Sailing”
“Sailing”
“Sailing lightly”
—Cab Calloway
My FIL (who’s almost 92) will say “right on!!” as a congratulatory exclamation. Has anyone used that since the era of Shaft? I would cringe every time he said it, but fortunately, it always seemed to be within a family group, so no risk of public embarrassment. He’d have truly been mortified if it had been pointed out that no one says that… Do they?
Can ya dig it?
Let’s blow this pop stand.
Mmmkay?
To be honest, I don’t think of anything when I say “sucks.” IT’s just its own term of either disappointment (“aw, that sucks!”) or a judgment (“aw, he sucks!”). I sure as heck hope my 5- and 7- year-old aren’t thinking of anything specific, either! 
Honestly, I don’t know how old I was before I made the connection that it may have some sexual meaning to it–probably deep into my teens or even twenties. I’ve known the expression “sucks eggs” from growing up and somebody being a “sucker,” of which neither had a sexual connotation to me, so I never sought to look out for one in “sucks.”
But, yes, that word has kind of drifted, although as a kid, it was never treated as even a mild expletive in my house (my parents are native Poles, though, so may not have the linguistic reference to judge its inappropriateness.) I do tell my kids, though, not to say it around polite company/ in front of a teacher or priest, as some people don’t share our view of the word.
Sucks/blows is the flammable/inflammable of mild expletives.
In 1990, CBS ran a sitcom based on the movie Uncle Buck. On the show, writers had Buck’s niece yell, “You suck!” at her brother. It caused a minor controversy at the time.
I recall a time when kids were pronouncing it like an almost-3 syllable word, which seemed objectionable. Like mocking. I only think it sounds right if the “l” is silent.
One word that truly has legs, though, is “nerd”.
I worked with an old guy (born in the '30s) who was so proud of himself and the Pre-Beatnik jazz musicians he hung out with. So many of their behaviors (marijuana) and language (“hip”) have survived, and the things they did to be “cool” are still considered cool.
Including the word cool.
“I can’t believe people are STILL using that word!” He then listed off a dozen other words and phrases, I said that I’d never heard any of them, and he lit up “But you still use COOL! Damn, we were cool…”
I never heard “nerd” until it was used on Happy Days.