Old conspirator, very dry, on our side (6)
I believe the answer is:
brutus
'old conspirator' is the definition.
'Brutus' can be an answer for 'conspirator' (I've seen this before). I'm unsure of the 'old' bit.
'dry on our side' is the wordplay.
'dry' becomes 'brut' (type of wine).
'on' says to put letters next to each other (in a down clue, letters appear on others).
'our side' becomes 'us' (our people or our side are us).
'brut'+'us'='BRUTUS'
'very' acts as a link.
Can you help me to learn more?
(Other definitions for brutus that I've seen before include "statesman who committed suicide in Macedonia" , "An honourable man, said Antony" , "Conspirator in the murder of Julius Caesar" , "He 12 against Caesar" , "Roman conspirator" .)