DuckCorp Dico

Found one definition

1.                 From WordNet (r) 3.0 (2006):
                   
   
   
                   
                     
   unfastener
       n 1: a person who unfastens or unwraps or opens; "children are
            talented undoers of their shoelaces" [syn: undoer,
            opener, unfastener, untier]