“Knee high to a grasshopper” (short)

“Beyond the pale” (outside social norms, I think. Maybe just strange)

“Dance maven”

“I’ll just do that in my copious free time…” (sarcastically, because you are too busy)

“Copacetic” (it’s all good)

“Heavy” (meaning important, grave)

I learned all of these thirty years ago from a man in his fifties. He was full of interesting expressions.