Girl, a climber (3)
I believe the answer is:
ivy
I believe this clue is a double definition.
'girl' is the first definition.
'a climber' is the second definition.
(thesaurus)
(Other definitions for ivy that I've seen before include "Common climbing evergreen plant" , "Climbing shrub; f. name" , "Clinging, parasitical plant" , "Evergreen climber" , "Clinging vine" .)