Agent the Spanish disgust (5)
I believe the answer is:
repel
'disgust' is the definition.
(I know that disgust is a more specific form of the action repel)
'agent the spanish' is the wordplay.
'agent' becomes 'rep' (short for representative).
'the spanish' becomes 'el' ('the' in Spanish).
'rep'+'el'='REPEL'
(Other definitions for repel that I've seen before include "'Drive back, repulse (5)'" , "Drive away like leper" , "oppose" , "See off" , "Turn away" .)