rearguard
Concise Oxford English Dictionary © 2008 Oxford University Press:
rearguard/ˈrɪəɡɑːd/
▶noun
- 1 the soldiers at the rear of a body of troops, especially those protecting a retreating army.
- 2 a reactionary or conservative faction.
– origin ME: from OFr. rereguarde.
'rearguard' also found in these Oxford entries:

