A word used to describe something completely awkward, weird, funny, or embarrassing. It could be something you saw, said, or experienced.
-You're buying something in a store and when you go to pay, you see the cashier and think: "OMG I just added her on Facebook last night and she's the cashier! That is so uhmish..."
-Checking out your reflection in someone's car and there happens to be someone in there. You walk away quickly saying: "That's uhmish..."