Holly aims to leave Emirates (4)
I believe the answer is:
tree
'holly' is the definition.
(thesaurus)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for tree that I've seen before include "- Frog; - house" , "A number" , "elder, maybe" , "Genealogy chart" , "Woody growth" .)