A pumpfaker is a person who states intentions to do something, and never follows through. A person who is notorious for making plans, but never following through.
A person who consistently Curves people.
Guy 1: Tamia said she was gonna come over, and never texted me back.
Guy 2: Yeah, she's a pumpfaker man, don't take anything she says to heart
When your fucking a bitch in the ass by a window with the lights off then tell her you'll be right back then your friend comes in and finshes the job while you wave at her through the window (she has no idea the friend is fucking her while you wave).