Dap, as in "give me some dap"... Around my way, it means that you bump fists with somebody you know as a greeting or as a way of agreeing on something. (you can also say "pound it"..) According to urbandictionary, this is where it comes from: "The Dap includes simple to very intricate series of rhythmic hand slaps, clasps, hand and arm gestures exchanged between two persons as a sign of personal greeting, respect and group solidarity. Has origin in greetings developed and practiced by members of Black Power organizations founded in southern California in the early 1970s and then became common place and outlawed practice among African-American draftees and soldiers stateside and abroad during the latter years of the Vietnam War." As far as the etymology, maybe it comes from "dapper"?