Janus-faced lock

from The Collaborative International Dictionary of English v.0.48

Janus-faced \Ja"nus-faced`\, a.
   Double-faced; deceitful.
   [1913 Webster]

   {Janus-faced lock}, one having duplicate faces so as to go
      upon a right or a left hand door, the key entering on
      either side indifferently. --Knight.
      [1913 Webster]