The feeling or acting like one is in a state of derp. In other words, it is the state of being where one is caught in whimsical silliness.
My corgi is being so derpsy today that he keeps tripping.
by jadders July 10, 2012
An adjective describing an individual who is trifling, or excessively irritating in nature or attitude.
That's some derpsy shit, man, that bro just knocked over my beer.
by imadeapoopie December 07, 2010