One Spaniard carrying another pot (9)
I believe the answer is:
marijuana
'pot' is the definition.
(synonyms)
'one spaniard carrying another' is the wordplay.
'one spaniard' becomes 'juan' (common Spanish name).
'carrying' indicates putting letters inside.
'another' becomes 'maria' (I am not sure about this - if you are sure you should believe this answer much more).
'juan' inserted into 'maria' is 'MARIJUANA'.
(Other definitions for marijuana that I've seen before include "grass" , "Hemp" , "Pot" , "3 Down" , "Wacky baccy" .)