It is a sound effect people often use to mean "yeah right."
example:
man 1: "Yo man, these shoes were like $100. Totally worth it."
man 2: "Psht. If you say so."
In texting, "psht" is typically used to express disbelief, dismissiveness, or annoyance, similar to a scoffing sound. It can indicate that the sender finds something unworthy of consideration or is unimpressed by what was just said. The term often conveys a casual, lighthearted tone, depending on the context.
If you mean slang as in internet slang, then it means "Certified Old Fart".
Slang is slang It's the s' "LANG " uage.
In old slang, milkshake mean butt.
It is slang for having sex.
Dough is a slang word for money.
he means what does being a sponge mean in slang
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.
he is a diary of a wimpy kid psht giggles i love pete
Tat is also slang for tattoo
''Dill'' means ''idiot'' as australian slang.
Potted is slang for very drunk.