(oh) (my) gosh!
A mild exclamation of surprise, alarm, dismay, annoyance, or exasperation. ("Gosh" here is a substitution for "God," the use of which in an oath can be considered blasphemous.) Gosh, look at the time! How is it nearly midnight already? Oh my gosh! That cyclist nearly hit me! My gosh, Bill! Would it kill you to take out the trash once in a while?