Historian, no end of social climber (3)
I believe the answer is:
ivy
'climber' is the definition.
(thesaurus)
I don't understand how the remainder of the clue works.
(Other definitions for ivy that I've seen before include "Four-year" , "Song: 'Poison --'" , "Hedera helix" , "Woody climber" , "Creeper plant" .)