To persist with an argument (typically on the internet) to the point beyond diminishing returns with the persistence of idiocy. A derpbate often involves two parties (often on the internet) in mild-to-extreme disagreement repeating each others points with slight modification in response to one another. A portmanteau of "Derp" and "Debate."
Sunday, sunday, SUNDAY, watch the socially inept Randroid debate the campus Communist in the CAGE on a politics forum! You do not want to miss one excruciating line of this ten hour derpbate!
by HeySeuss November 14, 2011
Like saying debatable only you say it when someone says something stupid that really isn't debatable.
*Stupid girl interrupts class*
Girl: "I have a really funny story to tell!"
Guy: "That's derpbatable."
Girl: "I have a really funny story to tell!"
Guy: "That's derpbatable."
by GES4 December 1, 2010