Debbish Share definition Flag Someone acting out stupidly, acting like a devolmentally disabled, via someone i once knew acting like a Debbie downer. one person: Im gonna smoke this whole bag of crack rocks. second person:man quit being Debbish Debbish by L.O.S.T 4 Life October 17, 2010 0 0 Get merch Get the Debbish mug. Buy Now — $32.95 See more merch