Support the Spanish cast (6)
I believe the answer is:
propel
'cast' is the definition.
(I know that cast is a more specific form of the action the throw)
'support the spanish' is the wordplay.
'support' becomes 'prop' (prop up can mean to support).
'the spanish' becomes 'el' ('the' in Spanish).
'prop'+'el'='PROPEL'
(Other definitions for propel that I've seen before include "Drive forwards" , "Derive of push forward" , "Launch" , "Cause to move forward with force" , "Drive or push forward as with oars" .)