From tyrant, I guarded island (7)
I believe the answer is:
antigua
'island' is the definition.
(I've seen this before)
'from tyrant i guarded' is the wordplay.
'from' indicates the answer is hidden within the clue.
'ANTIGUA' is hidden in the letters of 'tyrant i guarded'.
(Other definitions for antigua that I've seen before include "One of the Leeward Islands" , "warm island" , "Largest of Leeward Is." , "Caribbean island linked with Barbuda" , "holiday destination" .)