Reflect on one bishop being hugged by a thousand soldiers (6)
I believe the answer is:
Here is my best explanation:
'reflect' is the definition.
(mirroring is a kind of reflecting)
'one bishop being hugged by a thousand soldiers' is the subsidiary indication.
'one' becomes 'i' (roman numeral).
'bishop' becomes 'rr'.
'being hugged by' indicates putting letters inside (I've seen this in other clues).
'a thousand' becomes 'm' ('M' can be a synonym of 'thousand').
'soldiers' becomes 'or' (**).
'irr' inserted inside 'mor' is 'mirror'.
'on' is the link.
(Other definitions for mirror that I've seen before include "Reflect", "Glass - paper", "Reflecting surface", "Reflecting glass", "Reflector", "Alice went through one (Carroll)", "Common device for reflection", "Reflective surface", "It reflects images" and "Looking-glass".)