Come out - for example with army corps retreating (6)
I believe the answer is:
emerge
'come out' is the definition.
(synonyms)
'example with army corps retreating' is the wordplay.
'example' becomes 'eg' (short for 'exempli gratia', 'for example' in Latin).
'with' is a charade indicator (letters next to each other).
'army corps' becomes 'reme' (Royal Electrical and Mechanical Engineers).
'retreating' shows that the letters should be reversed in order.
'eg'+'reme'='egreme'
'egreme' reversed gives 'EMERGE'.
'for' acts as a link.
(Other definitions for emerge that I've seen before include "Emanate" , "Come out or surface" , "(Of facts) become known" , "Move out and become visible" , "Become gradually apparent" .)