Artificial intelligent assistant

retroguard

retroguard Obs. rare.
  [ad. med.L. retroguardia, -garda (Du Cange), obs. Pg. retroguarda.]
  = rear-guard1.

1574 H. G. Most Briefe Tables H ij b, And let another parte bee for a Vantgarde and Retroguarde to the raye.

Oxford English Dictionary

yu7NTAkq2jTfdvEzudIdQgChiKuccveC ba829ff44842f0491f1cb093788f2c2f