A mild oath. Roughly equivalent to saying "Jesus Christ" as an oath, but less severe, and used so as not to get stricken down for blasphemy.

same as saying "Jesus Christ!" but in a lighter manner. Usually used to express exclamation.

In the movie "Thelma and Louise", Thelma: "Geeze, Louise. That wasn't very nice." Many think this to be the origin of this expression.

oh my gooooodddd, i can't believe it.
when something is unbelievable.