Dry American conspirator (6)
I believe the answer is:
brutus
'conspirator' is the definition.
(I've seen this before)
'dry american' is the wordplay.
'dry' becomes 'brut' (type of wine).
'american' becomes 'US' (abbreviation for United States).
'brut'+'us'='BRUTUS'
(Other definitions for brutus that I've seen before include "He was last to stab Julius Caesar" , "senator in Rome once" , "associate of 24?" , "Honourable Roman" , "Murderer of Caesar" .)