tweaker's thumb Share definition Flag Forming of a giant blister or callus on your thumb from smoking soooo much meth. I can tell weather or not anyone has been smoking meth recently by seeing weather or not they've got tweaker's thumb(s). tweaker's thumb by Willie Tutu December 23, 2010 0 0 Get merch Get the tweaker's thumb mug. Buy Now — $32.95 See more merch