not so much a word as an action. when someone is talking to you and you dont really want to hear what they have to say or you just dont feel like listening you just go pssssss... and eventually they will get the point and shut up.
hillary: hey for once in your life could you pick up your damn clothes around here.
Me:psssssssss...(while she is talking)
Hillary: why are you making that hissing noise, stop making that hissing noise, what ever i'm leaving!
n. - The noise emmitted from a blow-off valve in a vehicle equipped with a turbo forced induction system when excessive back pressure is released. Excessive back pressure is created when the throttle is closed during gear changes or deceleration, causing turbo cavitation.
There is an orange SRT-4 here with black rims on it that has this blow-off valve thing all the time... like he just lets go of the gas when he is going 20 km/h and PSSSSSSHHHHHHH ...I mean I have an air compressor and if I turned it on and then undid the drain plug it wouldn't make so much PSSSSSSHHHHHHHing