Klickitat is a noun or adjective abbreviated from the phrase "click-a-tattoo." Klickitat is a low quality tattoo that looks like the person may have ordered it on a cheap online store or "clicked a tattoo." Usually tattoos of numbers (eg. 10642), dragons (excluding tattoos depicting famous dragons such as Smog or Puff) and Japanese characters (eg. hope, love etc.) are klickitat.
Mark: Hey Bethany, check out that girl's tattoo on her foot. I think it says, "10642." Oh wait, I read that backwards.
Bethany: Like, shut up, Mark. That is sooooooooooo klickitat. It looks like she ordered it straight from klickitat.com. Do you even, like, have good taste anyway?
Mark: I think that's a sweet tattoo; she probably got it done at Deep Roots; they do some good work.