The broad meaning of the word “derp” means stupidity or foolishness. Depending of the situation and sentence construction, derp relates to different variants of stupidity or foolishness.
As an interjection, derp is used as a response to an awkward or foolish person, action, situation or comment. As a noun, it simply means stupidity or foolishness. It means "to act foolishly" when used as a verb without an object, and when used with an object it means "to be foolish" or "to make fun of."
“Derp” originated in the late 1990s and early 2000 as alteration to duh, dur or der.