pffft
interj.
[IRC] A metamorphic expletive which can be used to convey emotion,
particularly shock or surprise, disgust or anger. The amplitude of the
reaction can be measured by counting intermediary fs. For example:
<jrandom> someone stole my hotdog
<fred> pffft
<frodo> Cthulhu stole my hotdog
<joe> pffffffffffffft!