The Collaborative International Dictionary of English v.0.48:

flypaper \fly"pa`per\ (fl[imac]"p[=a]`p[~e]r), n.
   A strip of paper that is coated with a sticky substance and
   suspended from an overhead object to trap and kill flies;
   also, a similar paper poisoned so as to kill flies on
   contact.
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

flypaper
    n 1: paper that is poisoned or coated with a sticky substance to
         kill flies