The Collaborative International Dictionary of English v.0.48:

Frame-up \Frame"-up`\, n.
   A conspiracy or plot for a malicious or evil purpose;
   especially, an act that incriminates a person on false
   evidence. [Slang]
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

frame-up
    n 1: an act that incriminates someone on a false charge [syn:
         frame-up, setup]