WordWeb Online

1. Spoiled and covered with eggs and larvae of flies
   "flyblown meat";
   - maggoty
    
2. Foul and run-down and repulsive
   "a flyblown bar on the edge of town";
   - squalid, sordid
    
3. Especially of reputation
   "a flyblown reputation"

See also: blemished, dirty, soiled, stale, unclean