Jack Threads Share definition Flag An advertiser on Urban Dictionary that promotes ridiculous Nigger costumes as "mens wear". Also any clothing worn while jacking off. I wouldn't even wear Jack Threads to masturbate. I prefer a wife beater and boxer shorts. Jack Threads by wolfbait51 May 20, 2011 0 0 Get merch Get the Jack Threads mug. Buy Now — $32.95 See more merch