Orange left out of tropical cocktail (7)
I believe the answer is:
apricot
'orange' is the definition.
(thesaurus)
'left out of tropical cocktail' is the wordplay.
'left' becomes 'l' (common abbreviation).
'out of' is a deletion indicator.
'cocktail' indicates an anagram.
'tropical' with 'l' removed is 'tropica'.
'tropica' anagrammed gives 'APRICOT'.
(Other definitions for apricot that I've seen before include "Fruit from a tropic" , "Yellow fruit" , "tree" , "Fruit resembling a peach" , "Juicy stone-fruit related to plum and peach" .)