For knights of old, a means of saving face (5)
I believe the answer is:
visor
'means of saving face' is the definition.
(I've seen this before)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for visor that I've seen before include "piece of armour" , "Part of suit of armour" , "Means of saving face" , "eye-shield" , "Movable shield on helmet" .)