In old slang, milkshake mean butt.
If you mean slang as in internet slang, then it means "Certified Old Fart".
Cool itself, unless you are using it to mean mildly cold, is a slang word. Just because it is old slang doesn't mean that it is not still slang.
Slang oud are 2 words in Afrikaans, with slang referring to a snake and oud referring to old.
To be Asian or to be a coward, slang from the old west.
OG in slang stands for "old gangsta." Ex. My father thinks he's a OG.
This is an old slang word for teacher
Old time expression for a big hit, a success.
OMGB stands for Old Man Gang Bang.
Old sailing slang meaning to be no longer in danger.
Limberlost is old slang for a dense, untamed forest or wilderness area. It was used in the early 20th century to refer to a place that was difficult to navigate or explore due to its dense vegetation.
Plain-Old-Data ........usually a built in or user defined type....
As old as language.