Pre-flake 

When someone decides not to commit to plans that haven't even been created yet.

Person 1: "We're probably going out again sometime next week if you wanna come."
Person 2: "No thanks, I'll probably be busy."
Person 1: "Bro, did you just pre-flake on us?"

Pre-flake by TheRealAndrewconda June 1, 2018

preflake 

When an invitee stipulates that unless another, more urgent, event comes up, they will attend your function.

"Yeah I'll probably be there...unless something major comes up."

"Dude, did you just preflake on me?"

preflake by omnoms September 4, 2009