Support post established in company? On the contrary (6)
I believe the answer is:
second
'support' is the definition.
(eg to second an idea is to support it)
'post established in company? on the contrary' is the wordplay.
I cannot quite see how this works, but
'company?' could be 'co' (abbreviation) and 'co' is found within the answer.
'post' could be 'send' (synonyms) and 'send' is found in the leftover letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for second that I've seen before include "Assistant in the ring" , "Lower < back" , "Flash" , "Instant - support" , "Back (but not first!)" .)