Rustic greeting by the Spanish king first (5)
I believe the answer is:
yokel
'rustic' is the definition.
(I know that yokel is a type of rustic)
'greeting by the spanish king first' is the wordplay.
'greeting' becomes 'yo'.
'by' is a charade indicator (letters next to each other).
'the spanish' becomes 'el' ('the' in Spanish).
'king first' becomes 'k' (1st letter of 'king').
'el' put after 'k' is 'kel'.
'yo'+'kel'='YOKEL'
(Other definitions for yokel that I've seen before include "Unsophisticated country person" , "Rustic - peasant" , "Countryman" , "rustic type" , "Unsophisticated rustic" .)