Spanish gentleman with important animal (6)
I believe the answer is:
donkey
'animal' is the definition.
(type of animal)
'spanish gentleman with important' is the wordplay.
'spanish gentleman' becomes 'don' (formal term of address for a man in Spanish).
'with' means one lot of letters go next to another.
'important' becomes 'key' (similar in meaning).
'don'+'key'='DONKEY'
(Other definitions for donkey that I've seen before include "stubborn type" , "Braying animal" , "This work is drudgery - by long-eared animal?" , "Braying quadruped" , "Domestic animal" .)