An abbreviation of "Do Not Steal". RPers often suffer delusions of grandeur, and when they create icons to use for their online roleplaying games, they often demand in the keywords that you do not steal the 100x100 boxes that they laborously edited for hours.
How to Piss Off Icon MakersEdit
Find someone with a bunch of icons that say "dns." (likely surrounded by alt-code quotation marks or some other ridiculous symbols), take them, upload them to your RP account without any credit, and make a post to dear_mun.