WordWeb Online

1. A seducer who ruins a woman
   "she awoke in the arms of her cruel undoer"
    
2. A person who unfastens, unwraps or opens
   "children are talented undoers of their shoelaces";
   - opener, unfastener, untier
    
3. A person who destroys, ruins or lays waste to
   "jealousy was his undoer";
   - destroyer, ruiner, waster, uprooter

Derived forms: undoers

Type of: bad person, individual, ladies' man, lady killer, mortal, person, seducer, somebody, someone, soul