noun

• (archaic) A lawyer who takes fees from both plaintiff and defendant.
  "But the thing which in eminent instances signalizes so exceptional a nature is this: though the man's even temper and discreet bearing would seem to intimate a mind peculiarly subject to the law of reason, not the less in his heart he would seem to riot in complete exemption from that law, having apparently little to do with reason further than to employ it as an ambidexter implement for effecting the irrational."
• (by extension) Someone who is two-faced; a double-dealer, such as a cheat or a crook.
  "One takes upon him temperence, holiness […], whenas indeed he, and he, and he, and the rest are hypocrites, ambidexters, outsides, so many turning pictures, a lion on one side, a lamb on the other."