The definition of iffy is:
(adjective) full of doubt or uncertainty, unsure
A: What are you going to do after graduating high school?
B: I’m not sure. The future is kind of iffy.
The kids wanted to go to the beach, but their babysitter refused to take them because the weather was iffy.
Customer: Excuse me, I’d like to send this meal back to the kitchen.
Waitress: Sure, may I ask why?
Customer: Something is wrong with it. It tastes a little bit iffy.
Waitress: Okay, I’ll get the cook to make you a new one.