The infinitive form of "yerp", used to express an emotion not definable within the english language, a cross between an affirmative "yes" and a confident flex of "yaaaaaaaa". The only acceptable response to someone saying yarp is a confident response of "yarp."
verb. Sally was flat broke and having spent weeks praying for money to no avail she decided to yarp for money. So she found a job ad in the paper, applied for it and a week later took home a pay check.
bob: Hey dude why did the chicken cross the road?
billy: Why!?
bob: To get to the other side!!
billy: YARP YARP YARP YARP YARP YARP YARP YARP YARP YARP YARP YARP YARP