Mexican, say, in Lisbon, Italian heading north (6)
I believe the answer is:
latino
'mexican say' is the definition.
'in lisbon italian heading north' is the wordplay.
'in' says the answer is hidden in the clue.
'heading north' says the letters should be written backwards.
'onital' is hidden within 'lisbon italian'.
'onital' backwards is 'LATINO'.
(Other definitions for latino that I've seen before include "Sort of American" , "Chilean possibly" .)