1. derp - Noun
2. derp - Verb
3. derp - Interjection
(slang) Draws attention to an act of foolishness or stupidity.
I put chips in my soup instead of crackers. Derp.
(slang) A placeholder for unimportant details, blah blah blah.
(slang) To act stupidly or foolishly
(slang) To make a stupid mistake
(slang, of eyes) To point in different directions; (of a person) To have a facial expression with one's eyes pointing in different directions.
(slang) A person who acts stupidly or foolishly; a person who derps.
(slang) A stupid mistake, stupidity.
(uncountable) The constant repeating of an opinion after facts have proved it incorrect, especially as a rhetorical tactic.
Source: en.wiktionary.orgDerp, maybe it's a spider. Source: Internet
The only thing missing is a “stump speech” consisting of “Derp, derp, derp, derp!” Source: Internet