The word has no meaning known to man on this planet.
However, On the planet "Zilpgoun" it is commonly known
as the act of softening a friends finger or toe nails by sucking on them and then chewing or bitting them off.
It is a cryptic that lives in the uninhabited areas of Pennsylvania It is part gerbil and part turtle. It's shell is covered in fur which keeps it warm. It has whiskers and fur like a gerbil and scales and a shell like a turtle. They are quite small creatures that live in wet or muddy areas and hate human interaction. They are called Derpa Turtles because the word derp used as a substitute for speech regarded as meaningless or stupid, or to comment on a foolish or stupid action. The A is added to make it plural to mean they are all foolish they are not the smartest creatures but have managed to survive
Did you hear about the man who was killed by those Derpa Turtles. No that could never happen they are too stupid.
A slang term for a hick, or redneck, they commonly drive large trucks with oversized tires. They think guns, tractors, Nascar, and everything with a large engine that makes noise is cool.
Herpa derpa is nonsense babble. When someone says something that makes no sense and sounds absolutely stupid you can respond with "Herpa derpa" as a quick painless way to avoid further conversation with whoever makes an idiotic statement. People use it to point out a stupid or ignorant remark or behavior.