Oops vs Nops - What's the difference?

As an initialism oops

is object-oriented programming system.

(en interjection)

Acknowledging a minor mistake.

Oops ! I left the lid off the ketchup.

Used sarcastically to acknowledge a major mistake.

''I just stepped on dog poo! Oops!

Oops, I didn't see you there.

Oops,... I locked my car keys inside the car.

* oopsy * uh-oh * whoops * whoops-a-daisy

(head)