* A small, quiet explosion or release of air: Like when a balloon pops softly or a can of soda fizzles.
* A sudden loss of air: Such as when someone laughs or coughs forcefully.
* Disdain or dismissal: Used to express that something is ridiculous or unimportant.
It can also be used in a more informal way to express surprise, amusement, or annoyance.
The meaning of "pftt" can vary depending on context and the speaker's intention.