Alligator pear (7)
I believe the answer is:
avocado
'alligator pear' is the definition.
(synonyms)
This is all the clue.
(Other definitions for avocado that I've seen before include "Evergreen" , "Large-stoned pear-shaped fruit" , "A dark green pear with cramy flesh" , "Fruity type" , "Dull greenish colour" .)