Brad brought up a climber (5)
I believe the answer is:
liana
'climber' is the definition.
(thesaurus)
'brad brought up a' is the wordplay.
'brad' becomes 'nail' (I've seen this before).
'brought up' shows that the letters should be reversed in order (down clues only).
'nail' back-to-front is 'lian'.
'lian'+'a'='LIANA'
(Other definitions for liana that I've seen before include "Jungle creeper" , "Rainforest climber" , "climber in the tropics" , "Woody climbing (usually tropical) plant" , "Tropical forest climber" .)