Climber in vivid red, athletic person (7,6)
I believe the answer is:
scarlet runner
'climber' is the definition.
(I know that scarlet runner is a type of coral pea)
'vivid red athletic person' is the wordplay.
'vivid red' becomes 'scarlet' (scarlet is a shade of red).
'athletic person' becomes 'runner' (runner is a type of athlete).
'scarlet'+'runner'='SCARLET-RUNNER'
'in' acts as a link.
(Other definitions for scarlet runner that I've seen before include "one going up the pole" , "Variety of bean" , "Type of bean" , "trained climber in garden" , "one to train on the pole in garden" .)